MOTI - Ironworkers Memorial Phase 2 Bird Management Plan · 1.2.1 Phase 1 Phase 1 consisted of an inventory and assess ment of bird presence and associated nests, feces and other

181217_Ironworkers Mem_Phase 2_Bird Manage_Final.docx

December 17, 2018

Prepared for:

Ministry of Transportation and Infrastructure Suite 310 – 1500 Woolridge Street Coquitlam, BC, V3K 0B8 Project No. 989531-15

01459 Ironworkers Memorial Second Narrows Crossing Bird Management Plan – Phase 2: Management Options

Prepared by:

Hemmera Envirochem Inc. 18th Floor, 4730 Kingsway Burnaby, BC V5H 0C6 T: 604.669.0424 F: 604.669.0430 hemmera.com

Photo Credit: C. Collinson

http://www.hemmera.com/

Ministry of Transportation and Infrastructure Ironworkers Memorial Bridge Bird Management Plan Phase 2: Management Options Project No. 989531-15

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TABLE OF CONTENTS

EXECUTIVE SUMMARY .............................................................................................................................. 1

1.0 INTRODUCTION .............................................................................................................................. 2 1.1 Overview ............................................................................................................................. 2 1.2 Project Description .............................................................................................................. 2

1.2.1 Phase 1 .................................................................................................................. 3 1.2.2 Phase 2 .................................................................................................................. 3

2.0 BRIDGE STRUCTURE AND BIRD MANAGEMENT ISSUES ........................................................ 5 2.1 Bridge Structure Overview .................................................................................................. 5 2.2 2010 Bridge Assessment Results ....................................................................................... 5

2.2.1 Critical Bridge Elements ......................................................................................... 6 2.2.2 Resultant Bird Management Recommendations ................................................... 6

2.3 Past Bird Management Measures ....................................................................................... 7 2.4 Phase 1 (2018 Bird Use) Results ........................................................................................ 7 2.5 Federal and Provincial Regulations .................................................................................... 8 2.6 Proposed Management Objectives ..................................................................................... 9

3.0 BIRD MANAGEMENT OPTIONS/STRATEGIES .......................................................................... 10 3.1 Desktop Review of Potential Management Options/Strategies ........................................ 10 3.2 Overview of Different Management Options ..................................................................... 10

3.2.1 Bird Removal ........................................................................................................ 10 3.2.2 Scaring Deterrents ............................................................................................... 12 3.2.3 Physical Deterrents .............................................................................................. 13 3.2.4 Chemical Deterrents ............................................................................................ 15 3.2.5 Coatings and/or Coverings .................................................................................. 15

3.3 Bird-specific Considerations ............................................................................................. 19 3.3.1 Double-crested and Pelagic Cormorant ............................................................... 19 3.3.2 Rock Pigeon and Northwestern Crow .................................................................. 21 3.3.3 Glaucus-winged Gull ............................................................................................ 21 3.3.4 Other Birds ........................................................................................................... 21

3.4 Evaluation of Management Options/Strategies ................................................................ 22

4.0 RECOMMENDED BIRD MANAGEMENT APPROACH ............................................................... 23 4.1 Physical Exclusion ............................................................................................................ 25

4.1.1 Exclosures at Critical Gusset Plate Connections ................................................. 25 4.1.2 Exclusion at Perforated Holes in Chord Members ............................................... 26

4.2 Physical Deterrents (Bird Spikes or Wire)......................................................................... 26 4.3 Cost Estimate .................................................................................................................... 27


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5.0 NEXT STEPS ................................................................................................................................. 29 5.1 Discussion with Ministry of Forests, Lands, Natural Resource Operations and Rural

Development ..................................................................................................................... 29 5.2 Bird Management Plan Implementation ............................................................................ 29

5.2.1 Pilot Program (Stage 1) ....................................................................................... 29 5.2.2 Effectiveness Monitoring ...................................................................................... 30 5.2.3 Phased Implementation (Stages 2 and 3) ........................................................... 31

6.0 CLOSURE ...................................................................................................................................... 32

7.0 REFERENCES ............................................................................................................................... 33

LIST OF TABLES

Table 1 Bird Management Options for the Ironworkers Memorial Bridge ...................................... 17 Table 2 Preliminary Cost Estimate for Proposed Bird Management Measures ............................ 28

LIST OF FIGURES

Figure 1 Ironworkers Memorial Second Narrows Crossing Bird Use Study Area ............................. 4 Figure 2 Conceptual design of exclosures. (A) profile view of conceptual design overlaid on

design drawings; (B) semi-profile view at 3-strut connection joint; (C) front-end view at 2-strut angled strut connection joint; (D) front-end view at 6-strut connection joint. ................................................................................................................ 24

LISTOFPHOTOS (APPENDIX A)

Photo 1 Ironworkers Memorial Bridge – Ground-based survey perspective. ................................ A.1 Photo 2 Pelagic cormorant nesting above pier, area where angled flashing or netting may

be appropriate. ................................................................................................................. A.1 Photo 3 Pelagic cormorant nesting on critical bridge elements (gusset plate, 3-strut), area

where angled flashing or netting may be appropriate. ..................................................... A.1 Photo 4 Nesting cormorants increasing in density, approaching Pier 15 from the south –

note that double-crested cormorant nest on horizontal bottom cross bracing (blue arrows) while pelagic cormorants nest in corners with an upper buffer to protect against predators (red arrows). Most double-crested cormorant nests are not on critical bridge elements, while most pelagic cormorant nests are. Grey line indicates substructure mid-line (going through 3-strut joint). ........................................... A.1

Photo 5 Some double-crested cormorants nest on critical bridge elements (centre gusset plate (6-strut), yellow arrows), while many do not (blue arrows). Pelagic cormorant nesting on critical bridge elements as well (red arrow, 2-strut perpendicular). Cormorant nests on critical elements may warrant custom designed exclosures. .......... A.2


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Photo 6 Close up of example of double-crested cormorants nesting on critical bridge elements (centre gusset plate (6-strut), yellow arrows), where custom designed exclosures may be appropriate. ....................................................................................... A.2

Photo 7 Pelagic cormorant nesting above pier, area where angled flashing or netting may be appropriate (note 2-strut angled gusset plate in centre). ............................................ A.2

Photo 8 Pelagic cormorant nesting in upper chord member (red arrow), area where angled flashing or netting may be appropriate............................................................................. A.2

Photo 9 Pelagic cormorant whitewash buildup in upper rafters, angled flashing or netting may be appropriate. ......................................................................................................... A.3

Photo 10 Pelagic cormorant nesting on upper horizontal chord member (red arrow), area where angled flashing or netting may be appropriate. ..................................................... A.3

Photo 11 Canada goose nesting on lower horizontal chord member above base of Pier 16 (yellow arrow). Where bird nests are not occurring on critical elements (e.g., Canada geese, glaucous-winged gulls), bird management strategies are not required. ........................................................................................................................... A.3

Photo 12 Holes in Pier 14 where rock pigeons were seen flying in an out (orange arrows), suspected nesting locations. Area where mesh netting affixed with epoxy would likely be an effective deterrent. ........................................................................................ A.3

Photo 13 Suspected northwestern crow or rock pigeon nest in vertical chord member (green arrow). .............................................................................................................................. A.4

Photo 14 Areas where custom designed cap/cover exclusion would likely be most effective deterrent (green arrows as example on one side of one vertical and one diagonal member). .......................................................................................................................... A.4

Ministry of Transportation and Infrastructure Ironworkers Memorial Bridge Bird Management Plan – Phase 2: Management Options Project No. 989531-15

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EXECUTIVE SUMMARY

Given ongoing concerns about how bird use of the Ironworkers Memorial Second Narrows Crossing (Ironworkers Bridge) may affect structural integrity, MOTI sought to identify appropriate management options to reduce bird use on the most critical bridge elements.

A previous assessment of bridge structural integrity was conducted in 2010, and summarized in the 1459 Second Narrows Bridge Evaluation Report (Delcan 2010). Bird management options recommended in that report included the installation of bird spikes and/or deterrent systems where large amounts of bird droppings have accumulated along the bridge. As these recommendations had not yet been implemented as of early 2018, MOTI contracted Hemmera to complete a follow-up avian use study and provide a more substantive review of bird management options for the bridge.

This report is a companion document to the 01459 Ironworkers Memorial Second Narrows Crossing Bird Management Plan – Phase 1: Avian Use Study (Hemmera 2018). The Phase 1 report summarized bird (avian) use of the Ironworkers Bridge, with the results of that report informing the management options provided within this follow-up (Phase 2) report.

Hemmera biologists observed a large cormorant colony, composed of pelagic (Phalacrocorax pelagicus) and double-crested (P. auritus) cormorants, nesting primarily between piers 14 and 16 during the breeding bird season, in spring of 2018. Many of these birds were observed nesting on more critical bridge elements (e.g., gusset plates), further substantiating the need for a management strategy. In addition to cormorants, nesting materials associated with use by rock pigeons (Columba livia) and northwestern crows (Corvus caurinus) were observed on some stiffeners of vertical and diagonal chord members, suggesting the need for additional approaches to manage bird use and minimize risk to bridge structural integrity.

A number of potential bird management options or strategies of bird deterrence were reviewed and summarized with respect to their anticipated value for the Ironworkers Bridge, through assessment of efficacy, environmental risk, cost, and similar considerations. The results of this review have indicated that physical exclusion is the only bird management measure that would have a high likelihood of success and warranted inclusion in a management approach.

Conceptual designs for physical exclusion options considered most likely to be effective were established, followed by preparation of approximate cost estimates to implement these recommended measures. Ultimately, a phased approach over three years is proposed with a pilot program to confirm efficacy in the first year.

In advance of any bird management strategy implementation, MOTI should contact MFLNRORD and ensure that this provincial agency is aware of MOTI’s plans for bird management on the Ironworkers Bridge. Although there are no specific regulatory requirements that limit the ability of a proponent to install devices or features that would prevent bird nesting on bridge structures outside the nesting season, discussion with MFLNRORD would recognize MFLNRORD’s role and interests in bird management (including cormorants) and help to ensure a favourable outcome.




1.0 INTRODUCTION

1.1 Overview

Hemmera Envirochem Inc. (“Hemmera”) was retained by the Ministry of Transportation and Infrastructure (MOTI) to inventory bird presence and usage of the 01459 Ironworkers Memorial Second Narrows Crossing (also known as the Ironworkers Memorial Bridge, referred to in this report as the “Bridge”) and provide management recommendations to prevent or mitigate associated build-up of bird nests and feces (or droppings). MOTI wants to gain a better understanding of bird usage of the Bridge (i.e., roosting and nesting) and determine how to best manage bird usage to protect the most critical elements of the Bridge, as bird feces can cause or exacerbate corrosion of structural components. The build-up of bird nests and feces poses ongoing risk to the long-term integrity of the Bridge, by introducing chemical compounds that promote corrosion and structural degradation. In addition, excessive quantities of bird feces may pose some human health risks to workers involved in periodic maintenance activities.

1.2 Project Description

The Bridge (Figure 1, Photo 1), which connects Vancouver to the north shore of Burrard Inlet (District of North Vancouver), has been long known to support a large number of birds that perch, roost, and nest on various parts of the structure. One of the major issues for bridges with extensive bird use, especially steel structures, is the diffusion of chemicals from bird feces which have the potential to weaken and corrode key support structures (Johnson 1990, Huang and Lavenburg 2011, Hansen 2013).

Due to the high chemical reactivity of bird droppings, the accumulation of these components on steel structures is known to have a detrimental effect on construction materials and health of infrastructure (Huang and Lavenburg 2011). While there remains some uncertainty with respect to the actual role that bird droppings play on the life cycle of typical steel bridges, the chemicals found in bird droppings are suspected to have played a role in the collapse of bridges of a similar structure, including the I-35W Mississippi River Bridge in 2007 (Lohn 2007, Subramanian 2008, Huang and Lavenburg 2011).

Bird droppings, including but presumably not limited to pigeon (which are likely the most studied species with respect to structural risk), contain ammonia and acids (Neal Langerman of the American Chemical Society, as cited in Lohn 2007). If the droppings are not washed away, they dry out and turn into a concentrated salt; when combined with water, this creates small electrochemical reactions that rust the steel underneath.

Cormorants, whose populations have been increasing on the Bridge in recent years (Carter 2014, Butler et al. 2015), can also damage structures with fecal contamination (US Army Corps of Engineers 2015). Corrosion damage to metal structures and painted finishes can occur as a result of uric acid in the bird droppings. Damage to structures is most likely to occur when high densities of nesting cormorants overlap spatially with key infrastructure locations.

The focus of this work was to study bird use and assess potential impacts on the most critical elements of the Bridge, such as bearing assembly, gusset plates, and stiffeners, with the goal of identifying bird management measures that would limit the chemical degradation of the Bridge due to bird-related materials, while still allowing inspectors and maintenance crews to be able to visually inspect the condition of these structural elements on a periodic basis. While other less critical structural components, such as




sway bracing, are considered, it is anticipated that their tolerance to bird related chemicals and materials is greater and thus mitigation measure can involve less intense methods such as periodic cleaning or methods that simply reduce their use by birds. Work in support of this bird management plan for the Bridge was conducted over two phases, as described below.

1.2.1 Phase 1

Phase 1 consisted of an inventory and assessment of bird presence and associated nests, feces and other related materials that could impact the structural components of the Bridge, including species, locations, and type of material. The findings of Phase 1 were summarized in the report 01459 Ironworkers Memorial Second Narrows Crossing Bird Management Plan – Phase 1: Avian Use Study (Hemmera 2018).

1.2.2 Phase 2

Phase 2 (i.e., this report) includes a comprehensive list and evaluation of potential management (i.e., prevention and/or mitigation) options, which includes, but is not limited to, the following:

1. removal of bird nests/feces/other materials on a routine basis (timing, methods, frequency), 2. prevention of future nest building/feces generation through physical or other barriers, 3. provision of alternative nesting/roosting locations, and/or 4. inclusion of any other options that may be considered effective at this bridge.

Evaluation of the Phase 2 options includes:

1. potential barriers/feasibility (e.g., safety requirements, timing constraints), 2. efficacy of approach (based on literature and/or regional examples), 3. anticipated costs (including installation and maintenance), 4. potential environmental risks/impacts and/or benefits, 5. regulatory requirements (e.g., BC Wildlife Act, Migratory Birds Convention Act and Species at Risk

Act) and/or 6. any other criteria that are determined to be important.

The Phase 2 recommendations are provided for consideration by MOTI bridge managers and are expected to be implemented in the coming years, through contracted services.

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Site Overview

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2.0 BRIDGE STRUCTURE AND BIRD MANAGEMENT ISSUES

2.1 Bridge Structure Overview

The 01459 Ironworkers Memorial Bridge is 1.3 km long crossing structure, which crosses the Second Narrows in Burrard Inlet and provides an essential transportation linkage between Burnaby and North Vancouver. The main section of the Bridge consisting of a 3-span steel haunched deck truss with a central drop-in span (Delcan 2010). Four steel deck trusses and nine concrete spans make up the approaches. The Bridge carries six lanes of traffic and two sidewalks. The Bridge is part of the Trans-Canada Highway and the BC MOTI disaster response route.

2.2 2010 Bridge Assessment Results

The Bridge was designed and constructed in the 1950s; bridges with similar configurations and of approximately the same age have had some structural issues elsewhere in North America (Delcan 2010). In 2010, Declan conducted an assessment and evaluation of the structural integrity of the Bridge. Specific issues of note were:

1. modern fatigue design guidelines for bridges were established in the mid 1970s and were not available when the Bridge was designed and built; and

2. the Bridge consists of a non-redundant structural system that is vulnerable to collapse.

The 2010 evaluation of the Ironworkers Memorial Bridge encompassed a detailed inspection and structural analysis with respect to load rating, fatigue analysis, and gusset plate adequacy. The scope of work for this assignment included the steel approach trusses and steel main truss of the Bridge.

The results of the inspection work are summarized as follows:

1. All deck joints along the Bridge were leaking to some extent, causing significant corrosion on bridge elements below.

2. Paint coating deterioration was estimated to cover approximately 50-60% of the Bridge. 3. No significant section loss due to corrosion over any continuous areas was found on the main truss

components. 4. No fatigue cracks were found in the main trusses. 5. A substantial amount of bird feces had accumulated in certain locations where it has led to, or could

lead to, significant corrosion. 6. The shrouds over the South Abutment bearings are heavily corroded and section loss has occurred.

Based on the Bridge’s condition at the time of inspection, and considering only the inspected elements, the Ironworkers Memorial Bridge was found to be structurally sound and adequate for the current traffic usage (Delcan 2010).

In order of priority, the recommended actions required to maintain the Bridge were (note: those actions related to bird management measures are highlighted in bold):

1. Non-Destructive Testing Program for the main drop-in span, bearings and tiedown pins. 2. Sandblast and recoat main truss members, gusset plates, and any secondary bracing that may

exhibit significant corrosion.




3. Install aprons under all deck finger joints to protect structural members below, such as floor beam bracing, and jacking girders. NOTE: It is important that the Maintenance contractor implement a regular cleaning program, to clean out the troughs.

4. Install bird spikes and/or deterrent systems where large amounts of bird droppings have accumulated (tops of bottom chords under diagonals, horizontal gussets for lateral bracing, above seismic isolation bearings, and tops of concrete piers).

5. Install bird covers at bottom chords above the seismic isolation bearings on the approach deck truss piers (piers 10 through 14).

6. Repair the shrouds over the abutment bearings where section loss has occurred.

2.2.1 Critical Bridge Elements

A series of comprehensive inspections on the four approach spans and the main spans were also undertaken in 2010. Specific structural components that were inspected included top chords, vertical and diagonal members, primary gussets, bracing members, tie down assemblies, and seismic isolation bearings. Special attention was paid to noted corrosion on the steel built-up members and connectors, distress in primary members and gussets, cracks, paint condition, debris and bird droppings on structural components.

The major issues with respect to the steel members on the Bridge relate to corrosion resulting from continuous contamination of de-icing salts passing through leaking compression seals and open deck joints, bird droppings, and condensation of seawater.

On the bottom chord members, typical corrosion was related to blisters developed on the top flanges and pack rust at the interface of built-up plates. Rust staining was typically observed in the primary gussets. However, localized blisters covering more than 50% of the outside surface were also found in some gussets.

The fixed bearings and isolation bearings were found to be in good condition. The main issue in these areas related to bird droppings and nests on both steel and concrete components. Some localized surface corrosion was typically seen on built-up plates and stiffeners.

2.2.2 Resultant Bird Management Recommendations

The level of corrosion and resulting section loss of the lower gusset plates, bolts and rivets was determined to have the possibility of significantly reducing the overall life span of the Bridge if not mitigated. Proactive measures were suggested to be undertaken to arrest the steel corrosion and deterioration, to avoid more comprehensive and more costly repairs that may be required in future.

Following the structural assessment conducted by Delcan, the installation of a bird spike system on selected areas of the Bridge was recommended (Delcan 2010). The most critical areas identified were top flanges of the bottom chord (especially under diagonals), top surface of horizontal gusset plates for lateral bracing, and top surface of concrete piers.

In addition, the installation of bird covers at the bottom chords above the seismic isolation bearings on the approach deck truss piers (piers 10 through 14) was also recommended.




2.3 Past Bird Management Measures

The bird management recommendations identified by Delcan in association with their previous assessment work (Delcan 2010) have not been implemented to the present date, but these recommendations did support this specific follow-up assessment effort and the resultant findings in this report.

Furthermore, it is noted that to the present date there have not been any known efforts to actively manage (i.e., preclude and/or reduce) bird use of the Bridge.

With respect to the removal of bird-related materials from this structure, MOTI bridge engineers have indicated that any such efforts have likely been limited to work completed in the 1990s. This previous work involved the removal of accumulated bird feces from the Bridge, with a specific focus on the cavities within the vertical and diagonal bridge members. Other than these efforts, which included the use of pressure washer and required extensive worker effort, there have not been any known focused efforts to clean bird-related materials from this structure.

2.4 Phase 1 (2018 Bird Use) Results

The focus of the Phase 1 work was to assess bird use of various Bridge structures to better understand the potential impacts of bird use on the most critical elements of the Bridge (e.g., bearing assembly, gusset plates, stiffeners, etc.). Six species of bird using the Bridge for nesting and/or other purposes (e.g., perching and roosting) were recorded in 2018. Active and inactive nests were documented on various components of the Bridge, with cormorants documented as the predominantly active nesting species (Photo 2, Photo 3, Photo 4, Photo 5, Photo 6, Photo 7, Photo 8, Photo 9, and Photo 10). Details on species specific nesting observations are summarized in the report Ironworkers Memorial Second Narrows Crossing Bird Management Plan – Phase 1: Avian Use Study (Hemmera 2018).

One Canada goose (Branta canadensis) nest was observed on the lower horizontal strut (bottom chord member) above the base of pier 16 (Photo 11). As Canada geese are large birds with relatively large nests and low agility, which more frequently nest closer to ground-level, nests of this species are not anticipated to occur regularly on the Bridge, nor were they anticipated to pose notable threats to the most critical elements of the Bridge. Two suspected glaucous-winged gull (Larus glaucescens) nests, one active and one inactive, were also observed. As applied to bird surveys conducted in previous years, all suspected gull nests were observed on exposed portion of bottom chords (EBA 2008). As these birds and their nests are also limited in number and typically only occur on bottom chord members on the Bridge, they are not anticipated to pose threats to more critical bridge elements.

Suspected inactive northwestern crow (Corvus caurinus) and rock pigeon (Columba livia) nests were distributed across the Bridge, especially near the southern portion, and were most commonly observed in the vertical and diagonal members (Photo 13 and Photo 14). Individual nests were often constructed on internal stiffeners within cavities in these members, accessed by perforated holes, and as such, were difficult to detect. Over time, it is understood that nesting debris and bird feces has tended to accumulate at the internal bases of these vertical members, causing potential metal degradation. Notably, the only past effort documented by MOTI with respect to the proactive removal of bird-related materials from the Bridge involved extensive efforts in the 1990s to remove bird feces from these cavities. Accumulations of bird feces and old nesting material in the bases of these vertical and diagonal members are difficult to effectively clean and may also pose health hazards, especially during any maintenance or inspection work. In addition to




nests within vertical and diagonal members, a number of rock pigeons were observed flying in and out of a hole on the inside of pier 14 (Photo 12). Similar to bird activity within cavities in vertical and diagonal members (Photo 13 and Photo 14), it is anticipated that removal of old nesting material and bird feces from inside a concrete pier would be challenging. A management approach to prevent northwestern crow and rock pigeon nests within areas that are challenging to maintain, especially cavities within steel chord members, was determined to be warranted.

Cormorants (pelagic (Phalacrocorax pelagicus) and double-crested (P. auritus)) were by far the most commonly observed bird species using the Bridge in 2018 (Photo 4, Photo 5, and Photo 6). A breeding cormorant colony typically includes individuals at various stages, from nest building and egg laying to incubation and fledging. Nest construction typically begins near the center of the colony, expanding outward (Garcia and Associates 2014). Older and more experienced individual cormorants typically initiate nesting activity early in the breeding season, with less experienced birds beginning later, occupying the periphery of the colony (Meier 1981, as cited in Garcia and Associates 2014). At the time of the survey efforts, it appeared that the colony core was established with some additional new nesting being initiated within more peripheral areas. Niche partitioning (by species) was also clearly observed: double-crested cormorants nested exclusively on horizontal chord members across much of the Bridge; pelagic cormorants nested exclusively on parts of the Bridge that offered some form of overhead protection (e.g., between gusset plates where horizontal chord members join, on top of piers, and on top chord members). Both species nested exclusively above open water, often within one metre of other nesting individuals. A management approach for cormorants nesting on more critical bridge elements (e.g., bearing assembly, gusset plates, stiffeners, etc.) was determined to be warranted; cormorants not nesting on these more critical bridge elements may be considered to pose less risk of structural degradation, and therefore may be allowed to remain on the Bridge.

2.5 Federal and Provincial Regulations

The provincial BC Wildlife Act protects vertebrate animals from direct harm, except as allowed by regulation (e.g. hunting or trapping). Under this legislation, any vertebrate species other than fish can be legally designated as endangered or threatened. The BC Conservation Data Centre (CDC) assesses the level that species or ecological communities are at risk of being lost, and, based on this assessment, assigns a provincial conservation status rank. Based on each species’ conservation status rank, an assignment to the red, blue or yellow list helps set conservation priorities and provides a simplified view of the status of BC's species. These lists help to identify species that can be considered for designation as "Endangered" or "Threatened." All bird species observed under the Ironworkers Memorial Bridge are afforded protection from direct harm under the BC Wildlife Act.

The federal Species at Risk Act (SARA) exists to prevent wildlife species in Canada from disappearing, to provide for the recovery of wildlife species that are extirpated (no longer exist in the wild in Canada), endangered, or threatened as a result of human activity, and to manage species of special concern to prevent them from becoming endangered or threatened (Environment and Climate Change Canada 2016). No birds observed on the Ironworkers Memorial Bridge are afforded protection under the SARA. Peregrine falcon (Falco peregrinus, Schedule 1 – Special Concern on the SARA), which was not observed in 2018, but has been historically observed in the area (eBird 2018), would be afforded protection under the SARA if any individuals were ever found nesting on the Bridge.




The federal Migratory Birds Convention Act, 1994 (MBCA), exists to protect and conserve migratory birds—as populations and individual birds—and their nests. Under the MBCA, no person shall, without lawful excuse, be in possession of a migratory bird or nest, or, buy, sell, exchange or give a migratory bird or nest or make it the subject of a commercial transaction. Cormorants and crows are not afforded protection under the MBCA, but pigeons, gulls, and geese are.

2.6 Proposed Management Objectives

The purpose of the Project was to evaluate bird use on the Bridge (Phase 1), identify key issues of concern from the perspective of potential impacts from bird-related materials (primarily bird feces) on this structure, and provide recommended bird management measures to address any key concerns (Phase 2).

In order to better define management objectives for this assignment, the authors of this report met with key MOTI bridge management staff to discuss the Phase 1 results and help guide further work on Phase 2. This meeting was held on July 5, 2018, at MOTI’s South Coast Region offices in Coquitlam, BC. Hemmera biologists provided a summary of the bird survey results from 2018, including an overview of key areas where bird nesting was occurring on the Bridge (primarily cormorants (double-crested and pelagic), rock pigeons, and northwestern crows). This led to discussions regarding nesting and other bird activity, including perching and roosting, that had been documented to overlap with the most critical structural elements of the Bridge (e.g., gusset plates connecting the bottom chord and bottom lateral bracing, typically in proximity to bearing assemblies) and the need to identify measures that would reduce the risk of ongoing adverse effects from bird use on the structural integrity of these elements. It was also noted that cormorants were the primary species nesting within these areas, especially between piers 14 and 16, and that pelagic cormorants in particular appeared to be selecting the most protected areas of these gusseted connections (e.g., well protected cover, including overhead cover provided by gusset plates). The apparently extensive use of internal cavity areas in vertical and diagonal chord members by rock pigeons and northwestern crows, with perforations facilitating bird access in these chord members, was also reviewed. Discussions about the challenges of cleaning bird-related materials from these cavities, or even of inspecting and assessing the structural integrity of steel inside these vertical chord members, led to agreement that preventing ongoing bird use of these areas should also be prioritized.

During this meeting, it was acknowledged that implementing measures to limit bird use on the entire bridge would be technically challenging and expensive. Furthermore, the ongoing presence of some species that could be considered ecologically important from a broader wildlife management perspective (e.g., cormorants) was noted, also suggesting preferential focus on key structural components where bird use posed the most structural concern. Preliminary discussions regarding some options that might be available for bird management at these focal points also occurred, with specific reference towards the potential use of bird spikes (primarily to deter cormorant nesting from critical gusset plate areas) and mesh coverings for perforated holes (primarily to restrict rock pigeon and northwestern crow nesting within chord member cavities). These discussions were preliminary and a full review of different bird management options, including but not limited to their anticipated efficacy for application to the Bridge and the specific bird species of concern, had, at this point, not yet occurred.

The purpose of the following sections is to review the full breadth of different bird management options that are known to have been applied within both North America and on a global scale (Sections 3.1 and 3.2), followed by bird-specific considerations for the birds of concern and how these species use the Bridge (Section 3.3), and finally a recommended bird management approach1 for the Bridge (Section 4.0).

1 The recommended approach outlined in the subsequent sections was presented MOTI bridge engineers and managers on

September 27, 2018. The feedback received has been incorporated into this report.




3.0 BIRD MANAGEMENT OPTIONS/STRATEGIES

3.1 Desktop Review of Potential Management Options/Strategies

A comprehensive evaluation of potential management options and/or strategies to provide for avoidance and/or mitigation of adverse effects from potential bird activity on the Bridge, with a specific focus on more critical structural elements, was conducted. It is understood that a wide range of the Bridge’s structural elements provide key roles in ensuring the overall structural integrity of the Bridge, however from this point forward in this report the term “critical structural element” is used to specifically reference those more critical structural elements (e.g., bearing assembly, gusset plates, stiffeners, etc.) that require the most focused attention with respect to bird management measures.

Eight websites offering bird control techniques were reviewed:

1. Pigeon Patrol (2018)

2. Bird Barrier America (2018)

3. Wildlife Control Supplies (2018)

4. Falcon Environmental Services (2018)

5. Skedaddle Humane Wildlife Control (Dowd 2017)

6. Westside Pest Control (2018)

7. Bird•B•Gone (2018)

8. Nixalite of America (2018).

Numerous options and techniques for bird management were reviewed and are summarized in Table 1.

3.2 Overview of Different Management Options

No one type of deterrent will typically work to exclude all bird species (Waterstaat 1999, Avery and Genchi 2009). Results of bird control methods vary greatly with location, bird species, and specific environmental circumstances (Waterstaat 1999). Five categories of bird management options were reviewed in support of this report (Table 1): removal of birds (e.g., live trapping, nest removal, culling); scaring deterrents (e.g., lights/lasers, mock predators, noise deterrents); physical deterrents (e.g., netting, spikes, wire, covers); chemical deterrents (e.g., toxicants); and coating/covering deterrents (e.g., gels, shock tape).Consideration towards the most relevant federal and/or provincial regulations, as described in Section 2.5, is referenced where appropriate both in Table 1 and in the following text.

3.2.1 Bird Removal

Bird removal techniques are those which would result in reduced bird abundances in a targeted area. There are various potential approaches to bird removal, such as culling (i.e., killing individuals), live trapping, removing nests, egg oiling, and implementing birth control measures.




3.2.1.1 Culling

Culling birds such as pigeons is an ineffective solution as it fails to deal with the root of the problem (Leone-Ganado 2015, PiCAS 2018). In a metropolitan setting, removal of birds from one piece of infrastructure would like result in the same infrastructure being used by other individuals in subsequent years. In addition to the ineffectiveness of culling, the killing of birds is prohibited under the BC Wildlife Act.

3.2.1.2 Live Trapping

Live trapping individuals and relocating them to suitable habitat elsewhere is also not effective, as individuals will typically return back to their breeding/roosting site (PiCAS 2018). Relocating live-trapped animals is a more effective technique when used with species that cannot fly, which obviously does not apply to birds that inhabit a bridge structure.

3.2.1.3 Nest Removal

Nest removal is also unlikely to be effective at deterring bird use on the Bridge as s34c of the BC Wildlife Act affords protection to occupied bird nests. This protection would require any nest removal activities to occur outside of the breeding season. Pigeons and crows may reuse nest sites from year to year, but are also known to construct new nests annually (Lowther and Johnston 1999, Verbeek and Butler 1999); gulls and cormorants are not known to have a high affinity for nest reuse (Hayward and Verbeek 2008, Hobson 2013, Dorr et al. 2014). Removing inactive nests outside of the breeding bird window may delay birds from returning to the Bridge, but it is not anticipated to be an effective means of bird deterrence.

3.2.1.4 Egg Oiling

Egg oiling is a method of egg treatment that is typically used for the control of ground nesting birds and involves the use of liquid paraffin (a highly refined mineral oil) to coat the shell of the egg in order to stop embryo development (Christens et al. 1995, Pigeon Control Resource Centre 2009). Egg oiling has been used successfully at preventing double-crested cormorant eggs from hatching (Shonk et al. 2004). However, as with nest removal, this would not be an appropriate option as most nests and their eggs (including cormorants) are afforded protection under s34c of the BC Wildlife Act.

3.2.1.5 Birth Control

Birth control measures for birds (i.e., OvoControl®), specifically targeting Canada geese and pigeons, has been developed and shown some success at reducing local bird populations (Bynum et al. 2007, Fagerstone et al. 2008, Caudell et al. 2010, MacDonald and Wolf 2013). As with culling, reducing pigeon or goose reproductive success is not anticipated to have a meaningful impact on bird use of the Bridge, as birds from other areas in proximity would likely recolonize the Bridge within a few years. Furthermore, approaches of this type would require permitting under the Wildlife Act and it is not clear that the regulator (Ministry of Forests, Lands, Natural Resource Operations and Rural Development; MFLNRORD) would issue permits of this type for cormorants.

3.2.1.6 Bird Removal Summary

Ultimately, complete exclusion of all birds from the Ironworkers Memorial Bridge is not the objective of these management options. Deterring birds from critical bridge elements, while still allowing for nesting opportunities on non-critical bridge elements, is instead the aim of this Phase 2 report as described in Section 2.6. As such, bird removal options are not the preferred method of bird deterrence on the Bridge.




3.2.2 Scaring Deterrents

Scaring deterrents are those which would elicit a behavioural response, resulting in birds leaving a targeted area. There are various bird scaring techniques, such as pyrotechnics (e.g., bangers, screamers), mock predators, reflectors, predator deployment (falconry), balloons, lasers/lighting, and sonic (speakers emitting distress calls, cannons) and ultrasonic noise.

3.2.2.1 Pyrotechnics

Pyrotechnics involve the detonation of a small explosive device, such as a banger or a screamer, to cause a startle reflex and promote an escape flight (Bishop et al. 2003). Pyrotechnics are effective at dispersing gulls, crows, and waterfowl, but habituation can occur rapidly if pyrotechnics are used frequently. Individuals may continue to flush but often return to the site of disturbance within hours. Pyrotechnics are labour intensive, can be difficult to deploy in some areas, and may cause a disturbance to other users of the Bridge (Harris and Davis 1998, Tvedten 2007).

3.2.2.2 Mock Predators

Mock predators or predator models are designed to resemble a predator, usually a hawk or owl, and can vary from very poor to very life-like imitations (Harris and Davis 1998). Predator models are designed to disperse and deter birds by mimicking the appearance/action of real predators. Most potential prey species react to predator models, however, the strength of the response varies from species to species (Bishop et al. 2003). In some cases, predator models can attract rather than repel birds as species such as crows often mob raptors or raptor models. Habituation to raptor models often occurs relatively quickly.

3.2.2.3 Reflective Devices

Reflectors, reflecting tape, and mirrors are occasionally used as birds may avoid these products initially due to their natural caution toward unfamiliar objects, and individuals may exhibit startle responses to the sudden flashes of light (Harris and Davis 1998). Reflectors, reflecting tape, and mirrors are inexpensive, but the effectiveness as a bird scaring technique is variable (Bishop et al. 2003). As these devices are only effective when they reflect sunlight, diurnal use would be the most effective. Because the biological basis is not strong, however, habituation is likely to occur quickly.

3.2.2.4 Predator Deployment

Predator deployment (e.g., falconry) is when trained falcons or hawks are employed by professional falconers to chase birds from specific areas by pursuing and occasionally killing them (Harris and Davis 1998). Falconry is one of the few scaring deterrent methods that birds do not habituate to (Waterstaat 1999); however, it is only effective for natural prey species of hawks or falcons (e.g., gulls, pigeons), and larger birds (e.g., cormorants), especially in expansive colonies, are unlikely to be deterred using this method (Harris and Davis 1998, Bishop et al. 2003, Cook et al. 2008).

3.2.2.5 Lasers

Laser or light deterrents are designed to startled birds from the strong contrast between ambient light and the laser beam (Bishop et al. 2003, Cassidy 2015). Lasers have shown promise as an effective deterrent at double-crested cormorant night roosts (Glahn et al. 2000, Blackwell et al. 2002), and other open habitat areas (Cassidy 2015), although there is evidence to suggest some birds are laser-resistant (Bishop et al. 2003). Lasers are expensive, require specialized training, and are only effective at night. In addition, lasers




and artificial lights could be a distraction for drivers using the Bridge or even an annoyance to local residents who have lines of sight to the Bridge.

3.2.2.6 Sonic Deterrents

Sonic deterrents can be used indoors and outdoors, day or night, and provide the widest area of coverage of the different categories of deterrent, with some devices covering up to 12 ha (Bomford and O’Brien 1990, Tvedten 2007, Desoky 2014). Sonic deterrents must be loud enough to be audible to the birds, must be within a frequency range the birds can detect, and must provide a biologically relevant message such that the birds depart (Beason 2004). Biosonic devices, (i.e., distress or alarm calls) may work at deterring some species, but species-specific calls must be played for maximum efficacy (Bomford and O’Brien 1990). Cannons, like pyrotechnics, can be an effective deterrent mechanism, but habituation can occur rapidly if used frequently (Harris and Davis 1998). Cannons are also a common source of nuisance noise complaints (Bishop et al. 2003). Studies looking at overall efficacy of sonic deterrents are inconclusive, with evidence suggesting that birds habituate with prolonged or frequent exposure (Bomford and O’Brien 1990, Harris and Davis 1998, Bishop et al. 2003, Cook et al. 2008, Soldatini et al. 2008). Sonic deterrents are often used to deter birds from orchards, fields, and roosts; the efficacy of these methods on bridges is unknown but presumed to be low due to the loud nature of near constant heavy traffic on the Bridge.

3.2.2.7 Ultrasonic Deterrents

Ultrasonic or high frequency sound producing devices (> 20,000 Hz) are marketed as an attractive measure for scaring birds as the noise they generate is not detectable to the human ear (Erickson et al. 1992). Effectiveness of ultrasonic noise deterrents on cormorants and gulls was investigated, and were found to have little, if any effect in dispersing birds (Erickson et al. 1992, Beason 2004).

3.2.2.8 Scarring Deterrent Summary

Bird management options also need to be sensitive to public interest (Tvedten 2007). Scaring techniques that involve the use of loud noises or bright lights to deter birds can be to the chagrin of local residents. Furthermore, if the need to breed supersedes the annoyance of the deterrent, birds will habituate to the deterrent, continuing to occupy an area despite suboptimal environmental conditions. Due to the uncertainty around efficacy and the fact that numerous approaches would be required to address each species of bird nesting on the Bridge, coupled with considerable challenges that may apply with respect to the necessary permitting (i.e., Wildlife Act) scaring deterrents are not considered an appropriate management option.

3.2.3 Physical Deterrents

Physical deterrents are the most effective means at deterring bird use from a desired area (Avery et al. 2001, Tvedten 2007, Vantassel et al. 2013, Desoky 2014). Physical deterrents are measures which physically prevent or exclude birds from entering or occupying a specific area. If birds are physically excluded from an area or feature, then bird use in these areas will not occur as long as the physical barrier is maintained.

3.2.3.1 Netting

Bird netting, when installed properly, prevents birds from gaining access to targeted areas (Dowd 2017). Netting is most useful in situations where the targeted area is confined, or for deterring birds from landing at specific sites such as preferred nesting locations (Harris and Davis 1998). Netting has proven to be effective at keeping predatory birds out of fish ponds (Parkhurst et al. 1987, as cited in Bishop et al. 2003),




and preventing bird damage to bales of plastic covered silage (McNamara et al. 2002, as cited in Bishop et al. 2003). The cost of a netting system depends on the area to be covered, the type of netting, and the associated support system (Bishop et al. 2003).

The use of netting can interfere with routine maintenance activities, however, reducing the level of exposure to allow for maintenance activities access may render the whole technique ineffective (Bishop et al. 2003). Nets can also be damaged by the wind or the accumulation of snow and ice, or displaced by stormy weather. If any rips or tears large enough to allow access to birds are developed, these areas will be exploited by birds. Generally, properly installed nets should last several years, but regular maintenance checks should occur to ensure the net is in good, functioning condition.

Netting, if properly installed, provides one of the most effective ways of preventing bird access. Its efficacy, however, is dependent on the correct mesh size being selected for the birds to be deterred, and on covering every gap or ledge that can be exploited by birds. Bird netting can be obvious or discreet, depending on the extent of netting installed.

3.2.3.2 Perch Deterrents

Perch deterrents (e.g., wire, spikes) are an effective tool that have deterred pigeons from many potential nesting sites (Seamans et al. 2007). Bird wire is installed on a flat surface to prevent birds from landing by making the area uncomfortable or impossible for birds to perch on (Dowd 2017). Bird spikes present a physical barrier that prevents birds from landing (Bishop et al. 2003). Bird spikes are only effective if they are designed for the bird species being targeted for exclusion. These systems are relatively expensive, and although relatively easy to install, they require monitoring and maintenance in order to remove debris which may accumulate, potentially reducing effectiveness. Of key note to this Bridge and in particular cormorants, the authors of this report were unable to confirm that bird spikes have been successfully deployed anywhere to prevent cormorant nesting activities.

3.2.3.3 Angled Slides

Angled flashing (slides) fitted onto ledges at an angle of inclination greater than 45° will prevent birds from perching or constructing nests on ledges (Andelt and Burnham 1993, as cited in Bishop et al. 2003). By eliminating perching, roosting, and nesting opportunities, angled flashing, designed in such a way to minimise bridge inspection/maintenance activities, could be considered appropriate for some applications on the Bridge but only if it allowed structural elements to periodically dry out and did not impact visual inspection activities.

3.2.3.4 Caps / Covers

Caps or covers are exclusionary measures that physically prevent birds from entering a targeted area with a hole or perforation. If designed to fit in a specific location, this technique would keep birds out for as long as the cap or cover is in place (Andrew MacBain, owner of Pigeon Patrol, pers. comm., August 31, 2018). Cap or cover exclusion devices are installed using a clamp or sealant around the outside to prevent birds from finding alternative entry points. Custom designed caps and/or covers are considered the most appropriate option for excluding birds (i.e., pigeons and crows) from perforated holes in vertical and diagonal chord members.




3.2.3.5 Physical Deterrent Summary

With respect to sensitive structural elements on the Bridge (e.g., gusset plates), the use of exclusionary devices (including “exclosures,” see Section 4.0, Figure 2) could provide similar benefits to caps/covers by physically preventing bird access and contingent upon proper design and installation.

Physical deterrents (i.e., exclusion techniques) are usually extremely effective (Bishop et al. 2003). Physical deterrents are most useful in situations where the risk is confined, or for deterring birds from landing at specific locations (e.g., nesting sites) (Harris and Davis 1998).The greater the extent of the exclusion measures, the more expensive. Use of these measures is therefore typically restricted to targeted areas to prevent costly damage.

3.2.4 Chemical Deterrents

Chemical deterrents are generally used to manage problem birds associated with food crops (Schafer and Brunton 1971, Curtis et al. 1994, Avery et al. 2001). Chemical deterrents are usually added to bait. When the treated bait is ingested, a distress response, which can last for up to 30 minutes, occurs (Transport Canada 1998). Aside from emitting distress calls, affected birds may become disoriented and exhibit erratic behaviour. This behaviour may alarm conspecifics, causing them to leave the area. Precaution must be taken, as too high a dose can be lethal. Chemical deterrent techniques are generally found to be more effective in laboratory trials than when deployed in the field (Bishop et al. 2003). The application of chemical deterrents has also been experimentally examined through a tear gas deployed using an integrated hazing system, which has shown promise as an effective deterrent on waterfowl (Stevens et al. 2000).

Chemical repellents have shown to be somewhat successful at deterring some species from feeding on crops, but the applicability of this technique to reducing bird numbers on infrastructure has not been studied. Administering chemical repellents would require the knowledge of specific feeding habits of each species using the Bridge. Both double-crested and pelagic cormorants forage for prey in the water (Hobson 2013, Dorr et al. 2014), rock pigeons feed on open ground on seeds, fruits, and human scraps (Lowther and Johnston 1999), northwestern crows feed on seabird eggs, intertidal invertebrates, insects, fruit, and human food scraps (Verbeek and Butler 1999), and glaucous-winged gulls feed on fish, marine invertebrates, carrion, and human refuse (Hayward and Verbeek 2008); however, the specific feeding habits of various bird species that use the Bridge are not well understood. The use of chemical repellents is not recommended due to both the complexities in administering to various species, all with different foraging techniques, and the potential side effects of the chemicals entering the marine environment below the Bridge. In addition, the permitting required prior to implement any such techniques (e.g., under the Wildlife Act) would undoubtedly be challenging to obtain from the regulator (MFLNRORD), especially when less invasive bird management methods are available.

3.2.5 Coatings and/or Coverings

Coatings and coverings are designed to be applied superficially, but do not physically exclude birds. There are limited options for coatings and coverings, which include gels and shock tape (electrified surface).




3.2.5.1 Gels

Gels are used to elicit an alleged tactile or visual aversion response in birds, reinforced by additional sensory cues (Stock and Haag-Wackernagel 2014). There are two types of gels: contact gels and optical gels. Contact gels are designed to cause a mild irritation when birds land on them, which is supposed to condition individuals to avoid a targeted area. Optical gels are supposed to deter birds without causing harm by repelling individuals visually, as the gel is perceived as fire within the ultraviolet visual range of the birds. Both of these gel types have shown some repellent effect, but some birds will habituate (Stock and Haag-Wackernagel 2014). Gels will also lose potency and become less effective over time, especially when exposed to the elements, as would be the case on the Bridge. Gels are not considered an appropriate management option.

3.2.5.2 Shock Tape

Shock tape is an mildly electrified strip that is installed to causes slight pain to birds when they use it as a perch (Seamans and Blackwell 2011). Activated shock tape has shown to be effective at displacing birds from treated areas, but individuals must experience the treatment first hand (i.e., flock members that did not touch the shock tape did not react to affected birds). Habituation to shock tape does not appear to occur. As birds must experience the shock, the entire portion of the Bridge that is currently used by birds would need to be covered. This would be technically challenging and would potentially pose an increased risk to bridge inspectors and maintenance workers.

3.2.5.3 Coatings and Coverings Summary

Similar to chemical deterrents, permitting constraints and challenges are another key consideration which limits the potential viability of coatings or other coverings for use on the Bridge.




Table 1 Bird Management Options for the Ironworkers Memorial Bridge

Technique Cost Estimate1 Efficacy2 Benefits Constraints Source Rating3

Removal

Culling $$ * Effective short-term reduction of birds. Ineffective long-term solution as individuals from adjacent habitats will re-colonize. Also prohibited under BC Wildlife Act. (Leone-Ganado 2015, PiCAS 2018) 1

Live traps $$ * Non-lethal form of removal. Ineffective as birds will fly long distances to return home. For most birds (including cormorants), requires permitting under the BC Wildlife Act. (PiCAS 2018) 1

Nest removal $$ * Short-term benefit only, as birds will return. Largely ineffective as active nest removal is prohibited under BC Wildlife Act for most bird species (including cormorants) and each species on the Bridge is known to construct new nests annually.

(Lowther and Johnston 1999, Verbeek and Butler 1999, Hayward and Verbeek 2008, Hobson 2013, Dorr et al. 2014)

1

Egg oiling $$ ** Effective treatment for reducing colony size. Eggs of most bird species (including cormorants) are afforded protection under the BC Wildlife Act.

(Christens et al. 1995, Shonk et al. 2004, Pigeon Control Resource Centre 2009) 1

OvoControl® $$ ** May reduce local populations temporarily. Not applicable to cormorants and not anticipated to be an effective tool at keeping birds (e.g., rock pigeons) from nesting on the Bridge as others will recolonize. Permitting requirements under the BC Wildlife Act would also apply for most species (including cormorants).

(Bynum et al. 2007, Fagerstone et al. 2008, Caudell et al. 2010, MacDonald and Wolf 2013) 1

Scaring

Bangers/screamers $$-$$$ *** Effective, especially if done randomly to prevent habituation. Labour intensive, difficult to deploy in some areas, birds can habituate, and may cause a disturbance to people who live near, or walk along, the Bridge. BC Wildlife Act permitting expected to apply.

(Harris and Davis 1998, Bishop et al. 2003, Tvedten 2007) 2

Mock predators $ ** Effective for some species short-term, highly economical choice for multiple indoor & outdoor operations. Habituation is common. No anticipated permitting requirements. (Harris and Davis 1998, Bishop et al. 2003) 2

Reflectors/mirrors $-$$ * Inexpensive. Variable effectiveness. Only effective during daytime, habituation likely. No anticipated permitting requirements. (Harris and Davis 1998, Bishop et al. 2003) 1

Predator deployment (falconry)

$$ *** Effective technique that does not typically result in habituation.

More commonly used at airports to exclude birds from flight paths. Not considered practical for cormorants or the Bridge in general. BC Wildlife Act permitting expected to apply.

(Harris and Davis 1998, Waterstaat 1999, Bishop et al. 2003, Cook et al. 2008) 1

Lasers $$-$$$ *** Effective at deterring double-crested cormorant from night roosts and open habitat areas.

Only effective in dark or low light conditions (i.e., crepuscular period or overnight). Unknown efficacy at deterring birds from constructing nests during daytime BC Wildlife Act permitting expected to apply.

(Glahn et al. 2000, Blackwell et al. 2002, Bishop et al. 2003, Desoky 2014, Cassidy 2015) 2

Sonic (speakers emitting distress calls, cannons)

$$ ** Provides the widest area of coverage - up to 12+ hectares; indoor & outdoor; species-specific; volume controlled, day/night/24-hr operation.

Results are inconclusive, evidence suggests birds habituate with prolonged or frequent exposure. BC Wildlife Act permitting expected to apply.

(Bomford and O’Brien 1990, Harris and Davis 1998, Bishop et al. 2003, Beason 2004, Tvedten 2007, Cook et al. 2008, Soldatini et al. 2008, Desoky 2014)

2

Ultrasonic $$ * Silent to humans. Silent to birds. Shown to be ineffective as bird deterrent. BC Wildlife Act permitting expected to apply. (Erickson et al. 1992, Beason 2004) 1

Physical

Netting/mesh $$$-$$$$ ****

Excludes birds by physically preventing them from accessing targeted area. Highly effective, if installed properly, and properly maintained. Can be designed for specific locations. Likely most effective method of bird deterrent for many components of the Bridge.

Expensive, especially for large areas. No anticipated permitting requirements. (Parkhurst et al. 1987, Harris and Davis 1998, McNamara et al. 2002, Bishop et al. 2003, Dowd 2017)

3

Spikes $$ **** Effective for some species. Relatively easy to install. Only effective if designed for bird species being targeted for exclusion. Relatively expensive. No anticipated permitting requirements.

(Bishop et al. 2003, Seamans et al. 2007, Dowd 2017) 2

Wire $$ **** Effective for some species. Relatively easy to install. Relatively expensive. No anticipated permitting requirements. (Bishop et al. 2003, Seamans et al. 2007, Dowd 2017) 2

Angled flashing (slides) $$ ****

Prevents birds from perching or constructing nests on ledges by causing materials to slide off. May work on some components of the Bridge.

May interfere with visual inspection and maintenance activities. No anticipated permitting requirements. (Andelt and Burnham 1993, Bishop et al. 2003) 2




Technique Cost Estimate1 Efficacy2 Benefits Constraints Source Rating3

Caps/covers $$$ ****

Effective measure preventing birds from entering a targeted area with a perforated hole. Custom designed caps/covers are likely the most effective method of excluding birds (i.e., pigeons and crows) from perforations in vertical and diagonal chord members on the Bridge.

Labour intensive to install. No anticipated permitting requirements. (Andrew MacBain, owner of Pigeon Patrol, pers. comm. August 31, 2018) 3

Chemical

Toxicants $$ ** Have shown some efficacy at deterring some species from certain crops.

Difficult to administer to various species with inconsistent foraging techniques. In addition, there could be concerns with chemical contamination of the marine environment. Would require a BC Wildlife Act permit, but also unlikely that regulator would issue permit.

(Schafer and Brunton 1971, Curtis et al. 1994, Transport Canada 1998, Avery et al. 2001) 1

Coatings/Coverings

Gels $$ ** Have shown some repellent effect. Some birds will habituate. Gels will also lose potency and become less effective over time, especially when exposed to the elements. Would require a BC Wildlife Act permit, but also unlikely that regulator would issue permit.

(Stock and Haag-Wackernagel 2014) 1

Mild electric shock track/tape $$-$$$ *** Shown to be effective at displacing birds from treated areas.

Individuals must experience the treatment first hand. Technically challenging to install and poses potential safety concerns for bridge inspection and maintenance crews. Would likely require a BC Wildlife Act permit, but also unlikely that regulator would issue permit.

(Seamans and Blackwell 2011) 1

1 Cost Estimate (considered each technique as stand-alone for entire bridge) = $ (thousands), $$ (tens of thousands), $$$ (hundreds of thousands), $$$$ millions 2 Efficacy = * (not at all effective), ** (somewhat effective), *** (mostly effective), **** (very effective) 3 Rating = 1 (not likely effective bird deterrent on the Bridge), 2 (potential for effective bird deterrent on the Bridge), 3 (likely most effective technique of bird deterrent on the Bridge)




3.3 Bird-specific Considerations

3.3.1 Double-crested and Pelagic Cormorant

Cormorants have demonstrated an ability to be successful in human modified environments. Although the presence of nesting cormorants on the Bridge was previously known, a more complete understanding was provided by survey work conducted in support of Phase 1 of this assignment. In 2018, more than 800 individual adult cormorants and 426 different active nests (including 298 double-crested cormorants and 128 pelagic cormorants) were documented (Hemmera 2018). Furthermore, evidence suggests that this colony is thriving and increasing in size.

Double-crested cormorant is provincially blue-listed (S3S4 – Special Concern (Vulnerable) to Apparently Secure) and globally listed as G5 (Secure) (BC CDC 2018). COSEWIC last assessed the double-crested cormorant in 1978 and designated them as Not at Risk. The breeding population in BC is in decline, while eastern populations are increasing (Chatwin et al. 2001, Pearson and Healey 2012).

Pelagic cormorant is provincially yellow-listed (S4 – Apparently Secure) and globally listed as G5 (Secure) (BC CDC 2018). The breeding population in BC has declined in the core of its range, according to recent surveys conducted during the breeding season (Chatwin et al. 2001, Hipfner 2015).

This cormorant colony is worth further consideration beyond bird management measures for the Bridge, as cormorants are fish-eating birds and this colony is located within 100 m of the outer estuary of Seymour River which is an important salmon and trout stream. Cormorant nesting occurs during the spring and summer months, with all nesting stages (especially the feeding of nestlings) extensively overlapping with smolt out-migration. This may be of some concern with respect to early marine survival of smolts originating from the Seymour River, or for that matter salmonid stocks associated with other tributaries to Burrard Inlet which out-migrate through the Second Narrows.

Previous studies on the survivorship of out-migrating salmonids from the Seymour River provide evidence of early marine mortality concerns. These studies have involved fish tagging and have indicated relatively high mortality rates for steelhead (anadromous rainbow trout; Oncorhynchus mykiss)) smolts near the estuary and in Burrard Inlet. These mortality rates have resulted in a practice by the Seymour Salmonid Society to release hatchery steelhead smolts near Point Atkinson for the past 11 or 12 years, in an effort to improve ocean survival (Marc Guimond, pers. comm., 2018). It appears likely that early marine mortality concerns may also apply to other salmonids, including but likely not limited to coho salmon (O. kisutch). One primary factor in early marine mortality of smolts may be the extensively degraded nature of the Seymour River estuary and nearby nearshore marine habitats; historic development activities (e.g., infilling and river engineering) have resulted in only a small fraction of remaining original habitat in the estuary (KWL 2017). Although some restoration work was recently conducted within the estuary near the railway bridge, the estuary continues to lack sufficient habitat heterogeneity, including extensive areas of cover and refuge features that are more typical of natural estuaries. In addition, overlap of the lower river and degraded estuary overlaps with an industrialized urban area that likely contains a mixture of toxicants, which may compromise fish health and increase their susceptibility to disease. Of key note to the subject of this specific report is the unusually high number of predators (e.g., birds, fish, seals, etc.) that also appears to be associated with the estuary. Predation risk on smolts is considered to be extremely high the first few days of seawater exposure, as these young fish swim typically swim with lower salinity waters near the surface (Balfry et al. 2011). Any elevated risk of predation would presumably be exacerbated by the current




condition of the estuary and the scarcity of habitat features which might otherwise afford smolts with cover and refuge from predators.

Prior to Bridge construction in the 1950s, or alternatively construction of the nearby hydro tower which has also historically supported cormorant nesting, predation by cormorants in the Seymour River estuary and nearby marine waters (including the Second Narrows) may have been lower. It appears unlikely, for instance, that a large cormorant colony would have flourished at this location prior to the establishment of the Bridge which is a large artificial nesting feature over the water at a prime foraging location in Burrard Inlet. Given these considerations, bird management measures that restrict unlimited expansion of the cormorant colony size may also benefit local salmonid stocks.

It should also be noted that double-crested and pelagic cormorants are native bird species of management concern which have experienced some decline within southwestern BC in recent years. Any final bird management plans for the Bridge which will alter cormorant nesting on the Bridge need to take this into account and will presumably warrant dialogue with MFLNRORD prior to implementation (see Section 5.1).

Given these considerations, bird management objectives for the Bridge should first and foremost protect the structure, while also trying to strike some balance between providing some bird nesting opportunities (including cormorants) and advancing broader ecological objectives (e.g., promotion of improved salmonid survivorship within Burrard Inlet). Any approach to bird management that better protects critical structural elements from impacts by nesting cormorants, while still allowing some opportunities for cormorants to nest on the Bridge, is expected to advance all of these objectives.

It is further noted that pelagic cormorants appear to preferentially nest in proximity to critical structural elements, where there is some form of overhead covering (e.g., gusset plates). This was typically in corners where two structural components meet, above piers, and within proximity to bearing assemblies and gusset plates (Photo 3, Photo 4, Photo 5, and Photo 6). Less often, pelagic cormorants nested in the top chord members (Photo 8, Photo 9, and Photo 10). In contrast, double-crested cormorant nests were typically on the bottom chord members with some nesting also on the centre gusset plates (Photo 4, Photo 5, and Photo 6) (Hemmera 2018).

Any bird management measures which focus on preventing cormorant nesting on or near critical structural elements could affect preferred nesting locations for pelagic cormorants more than it affects double-crested cormorants. Pelagic cormorants were, however, also noted to nest on top chord members. This species may also successfully nest on structural elements currently more preferred by double-crested cormorants, if apparently preferred locations are not available.

As top chord members and other potential nesting sites are well-represented and apparently under-utilized by nesting pelagic cormorants, it is anticipated that pelagic cormorants will continue to successfully nest on the Bridge. As a result, no mitigation or off-setting measures for the loss of existing cormorant nesting areas (e.g., establishment of alternate nesting sites, through installation of artificial features on the Bridge) are currently proposed. It is recommended that this be confirmed with follow-up monitoring, to further confirm the persistence of this mixed-species cormorant colony on the Bridge.




3.3.2 Rock Pigeon and Northwestern Crow

As documented in 2018 (Hemmera 2018) and in several previous surveys, rock pigeon and northwestern crow appear to frequently nest within cavity areas accessed by perforated holes in the vertical and diagonal chord members. In addition to nesting in these cavities, it appears likely that these bird species roost and perch on the bottom edge of these perforations or even within the cavity areas outside the breeding season. Although it is difficult to inspect these areas, maintenance activities undertaken in the 1990s involved cleaning bird feces and other materials from within these cavities and indicated the presence of extensive deposits of bird-related materials up to 1.0 m deep in some locations (MOTI bridge engineering staff, pers. comm., July 5, 2018).

Although some additional nesting may occur on horizontal chord members, the main area of concern for nesting rock pigeon is considered to be these cavity areas where bird feces can accumulate and may go both undetected and unchecked resulting in potential increased risk of corrosion.

Provincially, rock pigeon is considered Exotic (i.e., species that have been moved beyond their natural range as a result of human activity), and as such, does not have a provincial status ranking; globally they are listed as G5 (Secure) (BC CDC 2018). Northwestern crow is provincially yellow-listed (S5 – Secure) and globally listed as G5 (Secure) (BC CDC 2018). This species has benefited greatly from the activities of humans, and is not of conservation concern (Butler 2015).

Although perforated holes in vertical and diagonal chord members most likely to provide ease of access for rock pigeon and northwestern crow appear to be those which are closest to internal stiffeners within these vertical and diagonal chord members, the potential for perforated holes further away from these same stiffeners to provide potential access cannot be readily dismissed. Given these considerations, any bird management measures will need to focus on preventing any rock pigeon or northwestern crow access into these cavity areas.

3.3.3 Glaucus-winged Gull

Glaucous-winged gulls were noted to be nesting in relatively low numbers on the Bridge in 2018 (Hemmera 2018) and have also been observed in the past. Glaucous-winged gull is provincially yellow-listed (S4 – Apparently Secure) and globally listed as G5 (Secure) (BC CDC 2018). Most glaucous-winged gull activity was noted on the top of concrete piers or on bottom chords. As nesting by this species was not extensive and did not overlap with any critical structural elements, no specific bird management measures are considered to apply. Furthermore, it is noted that any measures to preclude cormorant nesting in critical structural elements (e.g., corners where two structural chord members meet, above piers, and within proximity to bearing assemblies and gusset plates) would obviously preclude potential nesting by glaucous-winged gulls in these same areas.

3.3.4 Other Birds

The only other birds that warrant mention with respect to the potential need to apply bird management measures are Canada goose and peregrine falcon.

Canada goose is provincially yellow-listed (S5 – Secure) and globally listed as G5 (Secure) (BC CDC 2018). Only one nesting Canada goose was observed in 2018, on the top of a concrete pier. As this species would be a very infrequent nester on the Bridge, no further consideration is required.




With respect to peregrine falcon, this species is mentioned not because of the potential need to prevent peregrine falcon nesting but rather to address the potential impacts of any bird management measures on this species for which some management concern applies.

Although active nesting by peregrine falcon has not been documented in recent years, the Bridge has potential to provide nesting habitat for falcon which may in turn hunt on rock pigeon and other birds that inhabit the general setting. The anatum subspecies of peregrine falcon is provincially red-listed (S2? – Imperiled, although ranking is uncertain) and globally listed as G4 (Apparently Secure) and was assessed as Not at Risk by COSEWIC in 2017; the pealei subspecies of peregrine falcon is provincially blue-listed (S3 – Special Concern or Vulnerable) and globally listed as G4 (Apparently Secure) and was assessed as Special Concern by COSEWIC in 2017 (BC CDC 2018). Both sub-species are also listed as Special Concern (2012) on Schedule 1 of the Species at Risk Act (SARA). Peregrine falcons are highly territorial (White et al. 2002) and the Bridge is unlikely to support more than one active peregrine nest at any given time.

The greatest potential for conflict between bird management measures for other birds that might in turn impact potential peregrine falcon nesting relates to cormorants. The proposed focus of cormorant management on the prevention of nesting at and near critical structural elements is, however, expected to leave considerable areas of potential falcon nesting habitat within the Bridge substructure. Notably, this would not be the case if extensive exclusion areas (e.g., large nets for full exclusion) were being considered.

Any efforts to address cormorant nesting by focusing on critical structural elements is not expected to actively promote peregrine nesting. Rather, it is anticipated that this proposed approach will maintain sufficient existing opportunities for peregrine falcon nesting so that the ongoing potential for this species to nest on the Bridge is not eliminated.

3.4 Evaluation of Management Options/Strategies

Ongoing effectiveness monitoring (follow-up monitoring) will help guide the overall management strategies. The success of the management options put forward in this report will be evaluated through the analysis of monitoring results. If monitoring results suggest that bird management is not as effective as expected, the prescribed approach may be adjusted within an adaptive management framework. Developments in ecological knowledge and effective exclusion techniques for cormorants may also result in modifications to management design and implementation.




4.0 RECOMMENDED BIRD MANAGEMENT APPROACH

A recommended approach for bird management on the Bridge is presented within this Section. This approach is based on consideration towards the Phase 1 bird survey results (Section 2.4), species-specific bird management objectives (Section 2.6), and a review of potential bird management options (Section 3.2).

This recommended approach primarily entails the application of physical deterrents which would exclude bird access from critical bridge structural elements. Some additional bird deterrence devices are also recommended in secondary applications and/or to augment some of the exclusion methods. In all cases, the installation of any physical deterrents (including any cleaning in advance of this installation) will need to be undertaken outside the critical bird breeding period for southwestern BC (i.e., March 15 to August 15). Furthermore, advanced raptor nest surveys will need to be made prior to any cleaning and installation efforts to ensure that year-round protected nests (e.g., peregrine falcon or bald eagle (Haliaeetus leucocephalus)) have not become established since the 2018 bird survey work was completed.

Recommended exclusion methods include installing “exclosures” (Figure 2) at gusset plates connecting chord members and horizontal bracing members, and mesh covering at perforated holes in vertical and diagonal chord members, as described below in Section 4.1. By definition, an “exclosure” is an area from which unwanted animals are excluded, or access is prevented. It is recommended that additional proposed bird deterrence devices would consist of large bird spikes, which would prevent bird activity (roosting, perching, or nesting) on horizontal gusset plate and bracing connections and on top chord members (see Sections 4.1 and 4.2).




Figure 2 Conceptual design of exclosures. (A) profile view of conceptual design overlaid on design drawings; (B) semi-profile view at 3-strut connection joint; (C) front-end view at 2-strut angled strut connection joint; (D) front-end view at 6-strut connection joint.

With respect to periodic cleaning efforts to remove bird feces and other bird-related materials, it is anticipated that any such cleaning can generally be avoided upon the successful implementation of these proposed physical exclusion efforts. Of note, it appears that bird feces and other materials (including nests) do not generally tend to persist over the long-term on the Bridge in most locations that are out in the open and seasonally exposed to wind and rain during the wet and stormy winter months (e.g., horizontal chord members).

Section 4.3 provides an overview of anticipated costs for installation of these exclusion features.




In addition, a monitoring framework is briefly described in Section 5.0 which should be used to ensure that different bird exclusion and deterrence features are working as planned and that any bird nesting (including cormorants) is primarily restricted to non-critical structural elements on the Bridge.

4.1 Physical Exclusion

Exclusion features are recommended as the primary measure to prevent bird nesting at critical horizontal gusset plate connections, which are identified as critical structural elements, along with perforated holes in vertical and diagonal chord members. Proposed exclusion measures for both horizontal gusset plate connections and perforated holes that access cavities in chord members are described in more detail below (Sections 4.1.1 and 4.1.2). Examples of where different recommended deterrent measures should be applied are in Appendix A (Photo 2 to Photo 14).

4.1.1 Exclosures at Critical Gusset Plate Connections

The primary purpose of exclusion measures at critical horizontal gusset plate connections will be to limit the potential for cormorants, including pelagic cormorants, which seem to prefer the protective cover provided by horizontal gusset plates. The installation of project-specific “exclosures” is proposed at each of these critical structural elements, as this will isolate these areas from bird use.

Based on consideration towards bridge design, critical gusset plate connections include those areas where bottom chord members meet veridical or diagonal chord members. As cormorants are known to prefer nesting locations over water, portions of the Bridge between piers 12 and 18 should be prioritized for installation of exclusion measures.

A review of Bridge design indicates there are approximately 190 different chord members between piers 15 to 16 and approximately 80 per span for remaining portions of the Bridge that are located above Burrard Inlet. This results in an estimated total of approximately 480 chord members that would warrant exclusion measures. Furthermore, it is noted that there are 4 different types of gusset plate connections that will require differently shaped exclosures (i.e., 2-struts perpendicular (Photo 5), 2-struts angled (Photo 7), 3-struts (Photo 3), and 6-struts (Photo 5 and Photo 6)). Of these, only the 3-strut joints along the substructure mid-line (Photo 4) will not require mirror-image versions for alternate sides of the Bridge.

Although further engineering design considerations apply, it is recommended that these exclosures be constructed of thick gauge galvanized or preferably stainless-steel mesh of a large mesh size (e.g., 4 cm) potentially with a rigid frame and bound with corrosion-resistant wire, fabricated near-site and then attached in location after the gusset plate connections have been properly cleaned of any bird feces and other bird-related materials. At least seven different design versions are anticipated to be required, including the mirror-image versions.

Those exclosures located along the substructure mid-line (Photo 4) should also have a steep multi-sloped upper surface or roof (minimum 60 degrees), with large bird spikes (minimum 17.5 cm tall, ideally stainless steel and designed for deterrence of perching by large birds including cormorants) at the peak of each roof (Figure 2).

Prior to installation, some cleaning of areas that will be located within each exclosure should occur (i.e., pressure washer and wet vacuum efforts).




4.1.2 Exclusion at Perforated Holes in Chord Members

Exclusion of birds currently accessing perforated holes in chord members and, in at least one location documented during the 2018 bird survey efforts in a concrete pier (i.e., pier 14) (Hemmera 2018), will isolate these areas from nesting birds (i.e., primarily rock pigeon and northwestern crow). An effort should be made to determine if there are any other holes in concrete piers that also require exclusion (Photo 12).

A review of Bridge design indicates there are approximately 5,000 perforated holes in chord members along the entire length of the Bridge. In addition, there appear to be two different perforated hole sizes that need to be accommodated. However, as MOTI staff pointed out (Zbigniew Radzimowski, pers. comm., September 27, 2018) the vertical chord members are more susceptible to basal feces and debris accumulation; the diagonal chord members have perforated holes along the underside, and as such, any bird feces or debris should clear out before reaching the base. This may reduce the overall number of exclusionary measures required at perforated holes in vertical and diagonal chord members.

Following extensive cleaning of areas within the chord members (i.e., pressure washer and wet vacuum efforts) and confirmation that these cavities are free of bird feces and other bird-free materials, breathable mesh covering should be installed over these openings. The mesh size should be approximately 1 cm, to ensure that not only the target bird species (i.e., rock pigeon and northwestern crow) but also smaller birds including songbirds are fully excluded. A recommended approach, which requires further engineering consideration and design efforts, would involve the fabrication of custom hole (vent) covers that are made completely of plastic or flexible plastic/rubber with corrosion-resistant steel (e.g., galvanized or stainless steel) that would be inserted for a snug fit in each perforated hole and attached with an appropriate adhesive or clamp.

Exclusionary measures at any perforated holes in concrete piers, if advanced, should be dealt with on a case-by-case basis with the installation of meshing for exclusion.

4.2 Physical Deterrents (Bird Spikes or Wire)

Some top chord members showed excessive bird feces accumulation from perching/roosting and do not seem to be seasonally cleaned by weather (e.g., winter wind and rain). This primarily appears to include major I-beams (or rafters) overlying additional horizontal beams (Photo 2, Photo 7, Photo 8, Photo 9, and Photo 10), that run perpendicular to the Bridge crossing and may therefore be less exposed to wind/rain.

Although these areas of bird feces accumulations do not overlap with the gusset plate connections at bottom chord members, and were difficult to properly assess during the 2018 survey work, some additional bird management measures are warranted. In this case, the limited extent of these areas and the fact that any nesting birds (including cormorants) are not expected to have an opportunity to construct nests if they are unable to land on these beams, deterrence rather than exclusion measures are proposed.

As with the large bird spikes proposed for installation on top of the exclosures and as described in Section 4.1.1, similar spikes (or alternatively wire) should be installed across the entire length and breadth of these areas to limit bird use. As with the installation of other physical deterrents, the cleaning of any existing accumulations of bird-related materials will have to be implemented first.




An estimate of the total number of I-beams where these large bird spikes (or wire) need to be installed requires further field evaluation, ideally at the end of the winter season so any persistent bird-related material accumulations can be identified. In the interim and for the purposes of this report, it is estimated that a total of 20 beam lengths (20 m long and 0.25 m wide) will require spike/wire installation.

4.3 Cost Estimate

Based on consideration towards the physical deterrents described in Sections 4.1 and 4.2, a high-level cost estimate has been developed and is provided below in Table 2.

This cost estimate should be considered as an approximate guide when the RFP package is being assembled. Furthermore, the unit costs are estimates and the number of different locations where different measures would need to be installed (e.g., critical gusset plate connections at bottom chord members, perforated holes in chord members, and I-beams above the top chord members with extensive bird activity) will depend on technical feasibility input from the company selected to design and implement the recommended management strategies.




Table 2 Preliminary Cost Estimate for Proposed Bird Management Measures

Technique Key Assumptions Unit Cost*

Proposed Staged Approach

Units Cost Units Cost Units Cost Units Cost Physical exclusion – exclosures at key horizontal chord member joints Stage 1 Stage 2 Stage 3 All Stages

Design costs 4 different types of exclosures, excluding mirror image versions (including engineering field survey and pilot implementation); estimated cost of $7,500 per exclusion type (Figure 2) $7,500 4 $30,000 N/A N/A N/A N/A 4 $30,000

Material costs - exclosure

480 sites for potential exclosure installation with cormorant nesting (over water sites, halfway between Piers 11 and 12 south to Pier 16) as priority for management; material costs averaged for 4 types of exclosures, of varying sizes; corrosion resistant mesh and wire, which may require rigid frame (e.g., aluminum tubing); unit cost of $600 based on an estimated material cost range of $450 (10 m of aluminum tubing at $5/m plus 10 m2 of stainless steel mesh at $40/m2) to $920 for a large exclosure (28 m of aluminum tubing at $5/m plus 20 m2 of stainless steel mesh at $40/m2)

$600 8 $4,800 176 $105,600 296 $177,600 480 $288,000

Material costs - bird spikes

on average, 2 m2 of bird spikes estimated to be required for each exclosure that is most likely to require a slope "roof" (50% of 480 exclosures); estimated unit cost of $11/m (derived from $3.25 for a 0.3 m long spike strip) $11 4 $44 88 $968 148 $1,628 240 $2,640

Fabrication costs

construct 480 exclosure "near-site", in advance of installation and based on design; assume 1.5 hr average per exclosure for a 2-man crew per chord member at $88/hr (same pro-rated crew rate as noted below for fall restraint work, but could potentially be reduced - based on $36/hr per worker, plus 20% markup)

$132 8 $1,056 176 $23,232 296 $39,072 480 $63,360

Cleaning costs** cleaning with pressure washers at 480 sites; cleaning with pressure washers vacs by workers using fall restraint equipment; assume 15-minute average for cleaning each chord member with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup) $44 8 $352 176 $7,744 296 $13,024 480 $21,120

Installation costs 480 sites for exclosure installation; installation by workers using fall restraint equipment, assume 30-minute average for installation on each chord member with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup) $88 8 $704 176 $15,488 296 $26,048 480 $42,240

Physical exclusion (exclosure) totals $36,956.00 $153,032.00 $257,372.00 $447,360.00 Physical exclusion – exclusion at perforated holes in vertical and diagonal chord members Stage 1 Stage 2 Stage 3 All Stages Design costs estimated cost to design and establish molds/etc. for fabrication of each unique perforated hole cover $1,200 2 $2,400 N/A N/A N/A N/A 2 $2,400

Fabrication costs

314 chord members consisting of 162 vertical (with 4 large oval and 18 smaller round perforated holes per chord member) and 152 diagonal (with 2 large oval and 6 smaller round perforated holes per chord member) for a total 952 large oval and 3,828 small round perforated holes to be covered; large oval perforations are approximately 0.20 m2 in size and smaller round perforated holes are approximately 0.04 m2 in size; anticipate use of stainless steel mesh and clamps with an average unit cost of $7.50/perforated hole ($40/m2 for stainless steel mesh and $1/clamp for 4 clamps; oval perforations cost $12/perforated hole and round perforations cost $6/perforated hole for a pro-rated unit cost of $7.00/perforated hole

$7 120 $840 4660 $32,620 N/A N/A 4,780 $33,460

Cleaning costs** 314 chord members (162 vertical and 152 diagonal) cleaning with pressure washers/wet vacs by workers using fall restraint equipment; assume 45-minute average for cleaning each chord member with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup)

$130 8 $1,040 306 $39,780 N/A N/A 314 $40,820

Installation costs

314 chord members consisting of 162 vertical (with 4 large oval and 18 smaller round perforated holes per chord member) and 152 diagonal chord members (with 2 large oval and 6 smaller round perforated holes per chord member) for a total 952 large oval and 3,828 small round perforated holes to be covered; installation by workers using fall restraint equipment, assume 15 minute average for installation on each perforated hole with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup)

$45 120 $5,400 4660 $209,700 N/A N/A 4,780 $215,100

Physical exclusion (perforated holes) totals $9,680 $282,100 $0 $291,780 Physical deterrents (bird spikes) – I-beams Stage 1 Stage 2 Stage 3 All Stages

Material costs 81 I-beams with an estimated total area per I-beam requiring spikes of 3.6 m2 (12 m length x 2 sides x 0.15 m) requiring spikes, for a total area of 292 m2; estimated unit cost of $80/m2 ($3.25 for a 0.3 m long spike strip, with 27 strips required per m2) $80 15 $1,200 277 $22,160 N/A N/A 292 $23,360

Cleaning costs** cleaning 81 I-beams with pressure washers; cleaning with pressure washers vacs by workers using fall restraint equipment; assume 30-minute average for cleaning each chord member with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup) $88 4 $352 77 $6,776 N/A N/A 81 $7,128

Installation costs 81 I-beams for spike installation, installation by workers using fall restraint equipment; assume 45-minute average for installation on each I-beam (both sides) with a 4-man crew per chord member at $175/hr (based on $36/hr per worker, plus 20% markup) $130 4 $520 77 $10,010 N/A N/A 81 $10,530

Physical deterrents (bird spikes) totals $2,072 $38,946 $0 $41,018 Stage 1 Stage 2 Stage 3 All Stages

Total $48,708 $474,078 $257,372 $780,158

* Note: all cost estimates are preliminary, based on initial evaluation of material quantities based on conceptual design; material costs are order of magnitude estimates without detailed evaluation based on input from potential suppliers; costs do not include wire given that it will be a very minor component of overall cost ** Completing cleaning activities at all, or the majority of, areas requiring implementation of bird management measures (rather than on smaller areas, as mobilization and set up costs are significant) would be a way to reduce costs (from a logistic perspective).




5.0 NEXT STEPS

Based on the recommended bird management approach described in Section 4.0, an implementation and monitoring plan is recommended and described below.

5.1 Discussion with Ministry of Forests, Lands, Natural Resource Operations and Rural Development

In advance of any bird management strategy implementation, MOTI should contact MFLNRORD and ensure that this provincial agency is aware of MOTI’s plans for bird management on the Bridge. Although there are no specific regulatory requirements that limit the ability of a proponent to install devices or features that would prevent bird nesting on bridge structures outside the nesting season, discussion with MFLNRORD would recognize MFLNRORD’s role and interests while helping to ensure a favourable outcome. In particular, it is noted that MFLNRORD has a role with respect to bird management and appears to be particularly interested with respect to important cormorant nesting colonies within southwestern BC.

A key aspect of these communications with MFLNRORD should include providing of a detailed and robust plan, including a monitoring component which demonstrates MOTI’s commitment towards ensuring efficacy of implemented measures and continued maintenance of the Bridge’s existing cormorant colony. In the unlikely event that follow-up monitoring demonstrates a negative change in cormorant nesting (i.e., measurable decrease in colony size based on total number of nesting birds, beyond areas where exclusionary measure as installed) which can be attributed to physical bird deterrents, it is recommended that MOTI be willing to develop and implement supplemental measures (e.g., artificial nesting platforms for pelagic cormorants).

5.2 Bird Management Plan Implementation

Regarding actual implementation of the final bird management approach, we suggest this plan be piloted in the first year and phased in in stages over the coming years, following the results of the pilot program. In particular, proposed exclosure installation to limit cormorant use of the Bridge could be implemented over several years to confirm positive results and also to defer costs over a longer time period. More specifically, primary cormorant nesting is currently focused on the area between piers 14 and 16 and there is potential that this cormorant colony might remain in this area even after exclosure installation is complete.

Furthermore, these exclosures represent a unique approach that has a high certainty of success but has not been specifically implemented in this manner on a similar bridge, as far as the authors of this report are aware.

5.2.1 Pilot Program (Stage 1)

An extensive review of potential bird management options to be considered for the Ironworkers Memorial Bridge was conducted; however, no case studies showing effective exclusion measures for various bird species using specific elements of the Bridge were found. As such, the authors of this report had to infer likelihood of success for the various bird management options based on similar settings (e.g., measures targeting species found on the Bridge, measures targeting birds using different pieces of infrastructure) and professional judgement.




As the proposed management options for excluding cormorants from critical bridge elements (e.g., gusset plates) put forward in this report are based on inferences and professional judgement, an initial pilot program is recommended in year one. The pilot program would include selecting an area of the Bridge with known large concentrations of cormorant nesting activity (e.g., one section of Bridge substructure between piers 14 and 15½ where cormorant nesting density is high, Photo 4, Photo 5, and Photo 6), and installing eight (8) project-specific exclosures within this test area. The estimated cost of piloting these bird exclosures (i.e., design, material, fabrication, cleaning, and installation costs) is approximately $40,000 (Stage 1, in Table 2), with installation taking approximately 2 or 3 days.

Excluding birds (e.g., pigeons and crow) from stiffeners within the vertical and diagonal chord members via mesh coverings is considered to be the best approach to prevent bird access to the chord members. Following discussions with MOTI staff (September 27, 2018), it was agreed that all perforated holes in the vertical chord members, and the lower section of perforated holes in the diagonal chord members, be covered. Furthermore, it was recognized that the installation of mesh coverings would need to be proceeded by thorough cleaning within the internal base of the vertical, and to a lesser extent diagonal, chord members. It is estimated that the cost of piloting the installation of 120 perforated hole covers (i.e., design, fabrication, cleaning, and installation costs) is approximately $10,000 (Table 2), with installation taking approximately 4 or 5 days. Although it is worth noting that cost savings could potentially be realized by cleaning all vertical and diagonal chord members on the Bridge and installing all perforated hole covers in one season, this could be logistically challenging to implement and would be in conflict with the objectives of a pilot program to verify and assess the proposed approach.

In addition, the installation of bird spikes to keep birds from top chord members (beams), should also be installed in an area where bird use was documented occurring in 2018 (e.g., between piers 16 and 17, or around pier 14). It is estimated that the cost of piloting installation of these bird spikes (i.e., cleaning and installation costs) is approximately $2,000 (Table 2), with installation taking approximately 1 day.

The total estimated cost of piloting these bird management strategies is approximately $50,000 (Table 2), with installation taking approximately 7 to 10 days. It is anticipated this work could be readily completed during the least risk window for breeding birds (i.e., August 15 to March 15). Effectiveness monitoring (Section 5.2.2) throughout the year would help to determine if the prescribed approach is working as anticipated, or if adaptations need to be made.

5.2.2 Effectiveness Monitoring

As the cormorant colony nesting location is primarily concentrated between piers 14 and 16, and there is potential that the cormorant colony might remain after exclosure installation is complete, ongoing effectiveness monitoring will be key to determining the need to adapt the current bird management strategy. These exclosures represent a unique approach that the authors consider having a high certainty of working but has not been specifically implemented in this manner on a similar bridge, as far as the authors of this report are aware.

Once the pilot program is complete, effectiveness monitoring would include surveys conducted near the beginning and end of the breeding bird season. This would be achieved by sending two biologists in a bridge traveler, documenting nesting activity along the entirety of the underside of the Bridge (using a similar methodology used in 2018, Hemmera 2018). If areas where exclosures have been installed remain free of nesting cormorants throughout the season, the strategy would be considered successful, and a phased implementation would follow. If, however, the exclosures were determined not to be reaching the desired outcome, adaptations to the existing strategy would be required.




5.2.3 Phased Implementation (Stages 2 and 3)

Providing that the pilot program indicates that the installed exclosures, perforated hole covers, and bird spikes/wires are achieving the desired outcomes, it is recommended that the treatment area should be expanded in subsequent years with a phased approach (two additional stages). By implementing these measures over time, MOTI bridge managers will have the ability to further confirm positive results and defer costs over a longer time period. A phased implementation would also allow some modest modifications, if potential improvements to design are determined through effectiveness monitoring.

If prescribed measures are determined to be ineffective, or not reaching the desired outcome, phased implementation should involve an adaptive management approach. This should entail a detailed review of what aspects are successful and which are not, with any necessary modifications applied as required.

5.2.3.1 Stage 2

Stage 2 implementation of cormorant exclosures, which would be focused on areas of primary cormorant use between piers 14 and 15½ (i.e., halfway between piers 15 and 16), would involve installation of an additional 176 exclosures (Table 2) at key horizontal chord member joints (e.g., gusset plates). The total estimated cost of Stage 2 exclosure installation is $153,000 and is anticipated to take approximately 50 days (33 days to complete exclosure fabrication (~$130,000), 6 days to clean all vertical and diagonal chord members (~$8,000), and 11 days to install (~$15,000)). While installation of these exclosures would need to be undertaken outside of the breeding bird window, fabrication could occur any time throughout the year.

Stage 2 implementation of perforated hole covers should involve installing mesh covers on perforated holes on the remainder of vertical and diagonal chord members on the Bridge that not completed during Stage 1 and would include the installation of an additional 4,660 covers (Table 2). The total estimated cost of Stage 2 perforated hole covers is $282,000 and is anticipated to take approximately 175 days (~$33,000 for fabrication, 29 days to clean all vertical and diagonal chord members (~$40,000) and 146 days to install all perforated hole covers (~$210,000)).

Stage 2 implementation of bird spikes would also extend to the remainder of the Bridge where these exclusionary measures were recommended (i.e., remaining 85 I-beams, Table 2). The total estimated cost of Stage 2 bird spikes is $40,000 and is anticipated to take approximately 12 days (~$22,000 for materials, 5 days to clean all I-beams (~$7,000), and 7 or 8 days to install all bird spikes (~$10,000)).

The total estimated cost of Stage 2 implementation is approximately $475,000 (Table 2), with installation taking approximately 205 days. This estimate of total effort is based on a single 4-man crew; bringing on additional crews would obviously reduce to overall timeframe required to install all Stage 2 bird management strategies. As a result, it is anticipated this work could be readily completed during the least risk window for breeding birds (i.e., August 15 to March 15).

5.2.3.2 Stage 3

Stage 3 implementation of cormorant exclosures, which would be focused on the remaining areas of potential cormorant use, would involve the installation of an additional 296 exclosures (Table 2) at key horizontal chord member joints (e.g., gusset plates). The total estimated cost of Stage 3 exclosure installation is $257,000 and is anticipated to take approximately 84 days (56 days to complete exclosure fabrication (~$218,000), 9 days to clean all vertical and diagonal chord members (~$13,000), and 19 days to install (~$26,000)).




While installation of these exclosures should be done outside of the breeding bird window, fabrication can occur any time throughout the year. As Stage 3 only involves the installation of exclosures (fabrication, cleaning sites, and installation), the aforementioned cost estimate and anticipated level of effort represents the extent of Stage 3 work. As with Stage 2 implementation, the estimates of time for completion for Stage 3 were based on the expected effort of one 4-man crew; bringing on additional crews would obviously reduce to overall timeframe required to install all Stage 3 bird management strategies. It is therefore anticipated this work could be completed during the least risk window for breeding birds (i.e., August 15 to March 15).

6.0 CLOSURE

We sincerely appreciate the opportunity to have assisted you with this project and if there are any questions, please do not hesitate to contact the undersigned by phone at 604.669.0424.

Kyle Routledge, B.Sc., R.P.Bio. Jim Roberts, B.Sc., R.P.Bio. Biologist Senior Biologist 604.669.0424 (104) 250.388.3584 (229) [email protected] [email protected]

mailto:[email protected]

mailto:[email protected]




7.0 REFERENCES

Andelt, W., and K. P. Burnham. 1993. Effectiveness of nylon lines for deterring rock doves from landing on ledges. Wildlife Society Bulletin 21:451–456.

Avery, M. L., and A. C. Genchi. 2009. Avian perching deterrents on ultrasonic sensors at airport wind-shear alert systems. Wildlife Society Bulletin 32:718–725.

Avery, M. L., E. A. Tillman, and C. C. Laukert. 2001. Evaluation of chemical repellents for reducing crop damage by Dickcissels in Venezuela. International Journal of Pest Management 47:311–314.

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APPENDIX A Photographs


December 2018 Page | A.1


Photo 1 Ironworkers Memorial Bridge – Ground-based survey perspective. Photo 2 Pelagic cormorant nesting above pier, area where angled flashing or netting may be appropriate.

Photo 3 Pelagic cormorant nesting on critical bridge elements (gusset plate, 3-strut), area where angled flashing or netting may be appropriate.

Photo 4 Nesting cormorants increasing in density, approaching Pier 15 from the south – note that double-crested cormorant nest on horizontal bottom cross bracing (blue arrows) while pelagic cormorants nest in corners with an upper buffer to protect against predators (red arrows). Most double-crested cormorant nests are not on critical bridge elements, while most pelagic cormorant nests are. Grey line indicates substructure mid-line (going through 3-strut joint).




Photo 5 Some double-crested cormorants nest on critical bridge elements (centre gusset plate (6-

strut), yellow arrows), while many do not (blue arrows). Pelagic cormorant nesting on critical bridge elements as well (red arrow, 2-strut perpendicular). Cormorant nests on critical elements may warrant custom designed exclosures.

Photo 6 Close up of example of double-crested cormorants nesting on critical bridge elements (centre gusset plate (6-strut), yellow arrows), where custom designed exclosures may be appropriate.

Photo 7 Pelagic cormorant nesting above pier, area where angled flashing or netting may be

appropriate (note 2-strut angled gusset plate in centre). Photo 8 Pelagic cormorant nesting in upper chord member (red arrow), area where angled flashing or netting

may be appropriate.




Photo 9 Pelagic cormorant whitewash buildup in upper rafters, angled flashing or netting may be appropriate.

Photo 10 Pelagic cormorant nesting on upper horizontal chord member (red arrow), area where angled flashing or netting may be appropriate.

Photo 11 Canada goose nesting on lower horizontal chord member above base of Pier 16 (yellow arrow). Where bird nests are not occurring on critical elements (e.g., Canada geese, glaucous-winged gulls), bird management strategies are not required.

Photo 12 Holes in Pier 14 where rock pigeons were seen flying in an out (orange arrows), suspected nesting locations. Area where mesh netting affixed with epoxy would likely be an effective deterrent.




Photo 13 Suspected northwestern crow or rock pigeon nest in vertical chord member (green arrow). Photo 14 Areas where custom designed cap/cover exclusion would likely be most effective deterrent (green arrows as example on one side of one vertical and one diagonal member).

MOTI - Ironworkers Memorial Phase 2 Bird Management Plan · 1.2.1 Phase 1 Phase 1 consisted of an inventory and assess ment of bird presence and associated nests, feces and other

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