Our Endangered Texas Native: The Golden-Cheeked Warbler

Learning More About Our Native Texan:

The Golden-cheeked Warbler

Central Texas is home

to a wide variety of

fascinating wildlife.

Among them are many

species of birds.

Photos: Jim & Lynne Weber, and City of Austin staff files

But of all the birds that can

be found here, only one

nests nowhere else in the

world but Texas.

Photo: Bill Reiner

Because every Golden-cheeked

Warbler was born in Texas, every

one is a native Texan.

Golden-cheeked Warbler (Setophaga chrysoparia)

Photos by John Ingram

about 5 inches long Both sexes have a black line through each eye,

across an otherwise immaculate yellow face.

Older males have a

black back and crown…

…and a black “bib”

Females and some young males have variable

amounts of green on the back and crown…

Warbler bills are slender, like forceps

… and

black on

the throat

A Look-Alike Migrant

Black-throated Green Warblers migrate

through central Texas in spring and fall. They

can look much like female Golden-cheeks.

Adult Golden-cheeked Warblers always have

bold black eye lines, and an immaculate white

vent area.

A yellowish wash at the vent is a distinctive

mark for Black-throated Green Warblers.

The back is green and the cheeks are yellow,

but the eye line is less prominent, and there are

dusky marks on the face.

A Gold-and-Black Bird at Your Birdfeeder

Lesser Goldfinch loves birdseed, especially thistle seed;

comes to birdfeeders

Golden-cheeked Warbler eats insects and spiders – not birdseed;

does not come to birdfeeders

Photo by John Ingram

is not a Golden-cheeked Warbler

The Golden-cheeked Warbler is a “forest-interior” species. The healthiest

populations are in large patches of mature, closed-canopy juniper-oak woodlands.


Golden-cheeked Warbler Habitat Requirements:

Tall trees with a high percentage of canopy cover are typical of their habitat.


Golden-cheeked Warblers need mature

Ashe juniper for nesting and food

(insects and spiders).



Champion Ashe juniper tree

New Braunfels

41 feet tall, 3.7 feet diameter

GCWAs are often seen on or near the ground,

so understory vegetation provides important

protective cover.


Photo by Jim O’Donnell

GCWAs often drink and bath in springs and shallow pools,

even crossing through neighboring territories to do so.



Hatch-year (“teenage”) Golden-cheeked Warblers

bathing and drinking from a puddle on a Preserve road

Film clip: Bill Reiner

They winter in pine-oak woodlands in the highlands of southern Mexico and Central America.

Where do Golden-cheeked Warblers Live?

These birds breed only in the juniper (also known as “cedar”) and oak woodlands of central Texas.

They migrate along the Sierra Madre Oriental in coniferous forest.


The Golden-

cheeked Warbler’s

range lies in the

Texas Hill Country,

west and north of

the Balcones Fault

Zone (Balcones

Escarpment)

Travis County supports some of the best and largest tracts of habitat in

the heart of the Golden-cheeked Warblers’ breeding range


Sketch of Friesenhahn Cave from the Bulletin of

the Texas Memorial Museum (1961)

Fossilized juniper and oak pollen from Friesenhahn Cave in northern Bexar County

date to the last ice age, about 14,000-20,000 years ago. – S. Hall and S. Valastro (1995)

Historical records provide evidence that the Hill Country has

supported juniper-oak woodlands for a very long time.

Historical photo of Bull Creek, below Cat Mountain and RM 2222, looking NW

(early 1900s)

Historical photo of a ravine near Wild Basin/Vireo Preserve, prior to clearing

-- William Bray (1904)

Historical photo of a ravine near Wild Basin/Vireo Preserve, following clearing

-- William Bray 1904

“[Golden-cheeked Warblers] are nowhere abundant, and only to be met

with in the thickest cedar brakes, and as these are fast being cut and

burnt out, the bird will no doubt become still more rare.” – H.P. Attwater, 1892

© John Ingram

Historical photo of land near Wild Basin/Vireo Preserve

being cut a second time (first cut ~1875). – Wm Bray (1904)

Unfortunately, a very limited

range makes these birds

vulnerable to habitat loss.

Unfortunately, a very limited

range makes these birds

vulnerable to habitat loss.

In 1990, the U.S. Fish &

Wildlife Service agreed,

and listed the species as

endangered.

Regulations slowed the

rapid loss of the birds’

habitat, but also caused

headaches for developers,

especially in fast-growing

urban areas such as Travis

County.

To ease the conflict, the

City of Austin and Travis

County applied for a U.S.

Fish & Wildlife Service

permit for a Habitat

Conservation Plan (HCP).

The basic plan allows

individual land-owners to

pay a mitigation fee to

develop their land. The

fees collected would be

used by the City and

County to purchase land as

a sanctuary for this and

other endangered species.

The approved plan is the

Balcones Canyonlands

Conservation Plan (BCCP),

the first multi-species HCP

in the country. The land

protected under this plan is

the Balcones Canyonlands

Preserve (BCP).

With the sprawl of cities

along the Interstate 35

corridor, biologists feared

for the species’ survival.

A Biological Advisory Team recommended

protecting 125,000 acres in Travis County to be

certain that this important population would survive.

A preserve that large was considered not feasible,

politically or economically, so a compromise of

75,000 acres was proposed.

The BCP partners determined that this second

proposal would also not be attainable, but 30,000

acres would be.

To reach a minimum viable size for the

population, the U.S. Fish & Wildlife Service

committed to creating a national wildlife refuge of

40,000 to 44,000 acres to protect the species.

(That refuge is the Balcones Canyonlands

National Wildlife Refuge.)

In addition to the warbler, the BCP

also protects habitat for the

endangered Black-capped Vireo, and

6 endangered karst invertebrates.

Establishing the Preserve

The Balcones Canyonlands Preserve (BCP) is not

a single preserve but a system of preserves

owned and managed by these partners.

City of Austin

Travis County

Private Landowners

Strengthened by Partnership

Lower Colorado River Authority

The Nature Conservancy

Travis Audubon Society

But preserving the land is only the first step…

Measures: How

Are They Doing?

• Dispersal – do individual warblers shift locations?

• Abundance and density

• Pairing success – whether males

attract mates

• Reproductive success – whether pairs

successfully raise young, and how many

(fecundity)

• Survival – what proportion of the birds return

to breed from the wintering range

• Territory mapping

• March 15-May 25

• Prime habitat: 10 visits

• Transitional habitat: 5 visits

• Productivity

• March 15-June 15, based on

behavioral observations

• 1 person per plot

• Average 6 hours/visit

• 60 hours prime habitat plots

• 30 hours transitional habitat

plots

Survey Methods

1998-2008

GCWA Population Viability &

Habitat Suitability Modeling Project

• Study conducted on the BCP under a 5-year contract with the

U.S. Forest Service

Photo by Gil Eckrich, Fort Hood

• Addressing 3 Key Questions:

– How many GCWAs are there on the

BCP?

– How are they doing?

– What management strategies can

best promote recovery of the

GCWAs and their habitat over the

long-term?

• Collaborative project with BCP partners

(and a great corps of volunteers!!!)

USFS Project Methods

• Intensive study plots across the

BCP

– Color banding

– Nest monitoring

– Territory mapping

• Point counts across the BCP

• Vegetation data for point counts & nests

Study Plots

• Color-banding

– Average >70% adult males banded

per plot

• Intensive territory mapping

– March 15-May 25, 10-20+ visits

• Typically 2 people per plot

• Average >130 hours/100 acres

• Nest monitoring, productivity

– March 15-June 15

Removing a Golden-cheeked Warbler

from a mist net

GCWA Color Banding

Altogether, we have banded 766 Golden-cheeked Warblers (2009-2014)

GCWA banding/re-sighting

Preliminary Results

• 162 adult males banded in 2011

94 adult males banded in 2012



667 adult males banded since 2009

• Male return rates:

– BCP = 44% in 2010

41% in 2011

56% in 2012

48% in 2013

46% in 2014

– Fort Hood 37-56% (8 yrs)

• 49 ad. females banded since 2009

GCWA banding/re-sighting

Preliminary Results

• In 2014, USFWS issued a permit

to band nestling Golden-cheeked

Warblers.

• Successfully banded 50

nestlings from 16 nests.

Photo by Amanda Aurora

Golden-cheeked Warbler

Nest Monitoring

To date, we have found and

monitored:

• 109 nests in 2011

• 151 nests in 2012

• 154 nests in 2013

• 194 nests in 2014


Most nests are found in Ashe

junipers, followed by live oak,

cedar elm, and other hardwoods

Results …so far To model the viability of the population, we need at least three years of data. But we do have preliminary findings:

• Higher density of territories in larger blocs of closed-canopy woodlands

Territories on JJ&T

transitional plot in 2010

Territories on Kent Butler

prime plot in 2010


Territories on JJ&T

transitional plot in 2010

Territories on Kent Butler

prime plot in 2010


• Older males make up more of the population in prime habitat sites

= second-year male

= after-second-year male

• About half of the males banded in 2009-2013 returned in subsequent years (44-56%) – return rates tend to be higher on plots with prime habitat


No banded males returned to JJ&T plot.

About half returned to Kent Butler plot.

• About half of the males banded in 2009-2014 returned in subsequent years (44-56%) – return rates tend to be higher on plots with prime habitat

• Very little dispersal




2009

2010

2011

Resighting/Dispersal

2012 Results

7 dispersal events

• 1.2 - 16 km

• 6 SY males, 1 ASY

However, >90% of

the banded GCWAs

found in subsequent

years have returned

to the same area

• Very little dispersal

• Pairing success generally averages more than 90%, especially on prime plots




Photos by John Ingram

• About 1/2 of males banded returned in subsequent years (44-56%) – return rates higher on plots with prime habitat

• Averaged 63-78% from 2009-2013

Results …so far

Breeding success (% territories fledging young)

• Tends to be higher on prime plots and for older males

• Variable statistics, partly from difficulty of finding all young when they leave the nest.

Reproduction (# of young/site)

• Largest patches of closed canopy woodlands have the highest reproductive output (Bull Creek, Cypress Creek, North Lake Austin macrosites)

• Study plots in smaller habitat patches (Barton Creek, West Austin) and young/recovering woodlands have the lowest reproductive output

• Lower success rate on small, isolated patches and young/recovering woodlands

To model the viability of the population, we need at least three years of data. But we do have preliminary findings:

So… How are the Golden-cheeked Warblers doing?

Range-wide:

• Many estimates of population

• Habitat loss continues, so likely a

downward trend On the Preserve:

• Population appeared

stable through 2012, but…

• Before 2009, counting un-banded birds

• Truly stable? Or constantly

supplemented by displaced birds?

• Extreme heat & drought of 2011 killed

many trees in some areas

• In 2013, few birds where trees died

• Where trees survived, higher densities

of birds in 2013…

• …but lower reproductive success

• Endangered status based upon

loss of habitat

• Endangered Species Act has led to

protection of some habitat, but allowed

some destruction as compromise.

• Re-growing suitable old-growth

habitat will take several decades to

a century or more.

Photo: Nancy Norman

Photo: Nancy Norman

• Reproductive success appears to have

been good for 2014.

Photo: Paul Brick The more data we collect, the more we learn

about:

• What are the characteristics – tree cover,

types of trees, understory, etc. – of habitat

where successful nests are built, and what

can we do to improve those features on

less-than-optimal sites

• How we can help these Native Texans

continue to thrive!

• Where and which birds are having the

most success raising young.

• Minimizing the threats from predators…

and people.

Barton Creek Wilderness Park/Greenbelt

So where can I see a Golden-cheeked Warbler?

Wild Basin Wilderness Preserve

Emma Long Park (City Park)

- Turkey Creek Trail

Travis Audubon’s Baker Sanctuary

Laguna Gloria

Bull Creek Greenbelt

St. Edwards Park

Cypress Creek Park, Lake Travis

Hamilton Pool

Balcones Canyonlands National Wildlife Refuge

- Warbler Vista

Golden-cheeked Warbler

fledglings taking a bath

Photo by: John Ingram

Thank you for protecting our

habitat!

To get involved with protecting warblers and their habitat, contact:

COA Volunteer Coordinator Louise Liller

[email protected]

Our Endangered Texas Native: The Golden-Cheeked Warbler

Science

golden cheeked warblers

adult goldencheeked

cheeked warblers live

birds habitat

female goldencheeks

habitat loss

birdfeeders photo

species of birds