Dietary Needs of Animals - Wildlife Center · • Value of “bird in hand” • Statistical problems • Lack of voucher specimens • Stomach content data often needed to exonerate

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Michael Lachance

Virginia Cooperative Extension

Wildlife Dietary Needs of Native

Plants and Animals

Wildlife Dietary Needs of Native

Plants and Animals

Susan L. Flader

4-H Wildlife Habitat Evaluation Program

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Why Are We Losing Wildlife?

– Loss of Habitat, Habitat Fragmentation• Increasing human population• Urban sprawl

– Other Human Activities• Introduced aliens, commercial hunting/fishing,

predator/pest control, pollution, exotic pet/plant trade

• Which Organisms Are We Losing?– Animals at Top of Food Chains– Habitat Specialists

Wildlife in a changing world

Losers• Passenger pigeon

• Carolina parakeet

• Bison

• Beaver

• Elk

Winners• Fox

• Raccoon

• Coyotes

Collisions with: Year of estimate Mortality estimate low Mortality estimate high

Wind turbines 2009 88,000 320,000

Towers 2008 4,000,000 50,000,000

Power lines 2001 10,000,000 154,000,000

Roads/vehicles 2005 10,700,000 380,000,000

Urban light 2009 31,158,000

Glass 2006 100,000,000 1,000,000,000

http://www.abcbirds.org/abcprograms/policy/collisions/index.html

Birds collected after colliding with buildings, Toronto 2009, by Kenneth Herdy, FLAP

•POPULATION GROWTH MODELS

–Exponential Growth vs. Logistic Growth

•CARRYING CAPACITY - The maximum number of

individuals of a given species that a habitat can

sustain indefinitely.

KCarrying capacity

Nu

mb

er

of

Org

an

ism

s

Time

Exponential Growth

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KCarrying capacity

Time

Optimal yield

(1/2 K)

Logistic Growth

Nu

mb

er

of

Org

an

ism

s

Carrying Capacity for Birds

• Dry western Plains 0.5 – 1 per acre

• Cultivated eastern farmland 1 - 3 per acre

• Deciduous eastern forests 1.5 – 10.5 per acre

Kuchler’s Map of Potential Vegetation of the United States.

Digital Atlas of the Virginia Flora

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Plants as part of wildlife diet

Plants parts for

wildlife food

• Fleshy nuts

• Nuts

• Seeds

• Vegetation (leaves,

stems and roots)

INSECTS AND OTHER

INVERTEBRATES

http://www.birdsasart.com/rootjpegs/loggerhead%20shrike.jpg

Vertebrates Analyze local conditions and existing

ecological communities

Though working with lists of indigenous plants

and animals you can avoid planting material

that has no value to species you are trying to

preserve.

Not only plants but invertebrates can benefit

from native landscape restoration

Pipevine Swallowtail

Caterpillar hosts: Pipevines (Aristolochia species), including Aristolochia californica, A.

serpentaria and others.

Adult food: Solely nectar from flowers including thistles (Cirsium species), bergamot, lilac,

common azaleas, teasel, petunias, verbenas, lupines.

Pipevine

SwallowtailEastern

Tailed-

Blue

Caterpillar hosts: Many plants in the pea family including yellow sweet

clover, alfalfa, various species of vetch, clover, wild pea, and Lespedeza.

Adult food: This butterfly has a low flight and a short proboscis, thus is

found at flowers close to the ground which are open or short-tubed.

These include white sweet clover, shepherd's needle, wild strawberry,

winter cress, cinquefoils, asters, and others.

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Wildlife Nutrition

• One of the basic interactions between an animal and the environment is through nutrition ingestion and metabolism of chemicals and

energy that animals need for maintenance and

production

• Food may dictate where a species can live and population density

• Operates through impacts on reproduction and survival

Potentially acts to influence

1. Age at puberty

2. Length of breeding season

3. Proportion of adults breeding

4. Number of ova shed

5. Prenatal and postnatal losses

6. Juvenile and adult survival

Nutrition

Habitat

Cover

Energy (CHO, fat)

Water Food

Protein MineralsVitamins

•Animals differ in part because of their digestive

systems

•An animal’s adaptations enable it to eat and

digest some foods well while inefficient at using

other foods

•Understanding these differences is important in

managing wildlife

Emerald Ash Borer

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An animal’s diet must provide proper nutrients at

the proper time

• Spring/Summer – growth in young animals

– protein, energy, mineral

thus diets switch often to insects in the

springtime

• Fall - increase body fat ; ovulation

– energy

– weaned young need protein

• Winter - Post-rut recovery; gestation

– energy

– maintenance protein requirement

Field Studies

Information gained:

• How, where, when food is taken

• % depletion of food supply

• Stomach contents don’t show environmental impact of animal presence and disturbance, i.e. wildlife damage

Difficulty of field studies

• Skill and experience of observers differ

• Value of “bird in hand”

• Statistical problems

• Lack of voucher specimens

• Stomach content data often needed to exonerate claims of damage

Laboratory Studies

Laboratory studies look at :

1. Crops

2. Stomachs

3. Droppings

4. Caches

5. Cheek pouches

6. Den and nest materials

Collecting and curating food from dead

animals

• Tools

– Sieves

– Forceps\Probes

– Scalpel

– Blower

• Reference material useful when identifying fragments

• Organs removed, wrapped in gauze with water proof label attached

• Vessels with preservative liquids

– Formalin (10% formaldehyde)

– 70% ethyl alcohol

• Bulky contents, soak in formalin and dry out

• Seeds, dry and add insecticide

To understand an animal’s interactions with its

nutritional environment, need to understand its

digestive system

Credit: David Hewitt, for syllabus for college course in wildlife nutrition:

http://users.tamuk.edu/david_hewitt/

Data card for Collected Food Items

1. Name of Species

2. Specimen Number

3. Date

4. Where collected

5. Where killed

6. Hour of death

7. Person making dissection and date

8. Condition of stomach

9. Condition of gullet

1. Percentage of:a) Animal matter

b) Vegetable matter

c) Gravel, etc.

d) Unknown material

2. Contents description area a) Include number of individuals

in stomach by species and

b) Each percent contribution to the contents

3. Person making the examination and date

4. Location of voucher materials

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Investigating Diet Through Post-

Mortem Food Items

Insure an adequate sample• Sample size or number

• Regional differences

• Seasonal differences

•

Data• Weight of animal

• Contents

– Estimated visually

– Measured volumetrically

– Counted out by kind, especially for predators

– Presence/absence

• Best to report by occurrence, numbers, and % of volume

Food habits of more

than 1,000 species of

mammals, birds, fish,

plus important plants as

food researched by U.S.

Fish and Wildlife

Service, based on

extensive stomach

content studies.

300 illustrations, maps.

Animal Groups Covered in Text

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4-H Wildlife Habitat Evaluation Program

http://www.whep.org/•Wildlife Management Concepts

•Wildlife Management by Regions

•Wildlife Management by Species

•Wildlife Management Practices

•Activities

1. Wildlife Foods

2. Interpreting Wildlife Habitat by Aerial

Photographs

3. On-Site Habitat Management Recommendations

4. Wildlife Management Plan

5. Urban Landscape and backyard Habitat Plan

Components of the Wildlife Habitat Curriculum

Wildlife Management Concepts

• Habitat Requirements

• Featured Species

• Species Richness

• Plant Succession and Effects on Wildlife

• Vertical Structure (Layering)

• Arrangement and Interspersion

• Edges and Contrast

• Area Sensitive Species

• Migration and Home Range

• Carrying capacity

• Pond Dynamics and Balance

• Wildlife Damage Management

• Food Webs

II Ecosystem CharacteristicsPYRAMID OF NUMBERS

For any specific location, there are many more plants

than herbivores, greater numbers of herbivores than

carnivores and seldom more than a few top carnivores.

General pattern in nature:

Primary Producers 1,500,000

H 200,000

C1 90,000

C2=1

Grassland (Summer)

Pyramid of Numbers(Individuals per 0.1 hectare)

Temperate Forest (Summer)

P 200

H 150,000

C1 120,000

C2 =2

Plant Succession

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FRAGMENTATION AND EDGE EFFECTAs the human population continues to grow, development

reduces and fragments remaining undisturbed habitat.

FRAGMENTATION AND EDGE EFFECTAs the human population continues to grow, development

reduces and fragments remaining undisturbed habitat.

• Minimum safe forest buffer given as 100 m. (330 ft.).

• For a 50-acre parcel, only 30 acres of “interior” forest

remains inside the edge.

50 acres 30 acres 100 m Edge

Edge Effect

•An edge effect may penetrate to 600 m.

•For a 100-acre parcel, only 10 acres of “interior” forest

would remain.

100 acres 10

acres600 m Edge

Edge Effect

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50 acres

50 acres 50 acres

50 acres

200 acres

100 m edge yields

30 acres x 4 = 120 interior acres

A 300 m edge yields

5.4 acres x 4 = 21.6 interior acres

100 m edge yields

157 interior acres

A 300 m edge yields

88.3 interior acres

Edge Effect and Fragmentation

50 acres

50 acres 50 acres

50 acres

200 acres

If a nesting pair of wood thrushes needs 10 acres of interior

forest habitat to successfully raise a clutch, calculate how many

pairs of wood thrushes will be successful in each of the above

forest woodlots, assuming a 100 m edge; a 300 m edge.

Edge Effect and Fragmentation

50 acres

50 acres 50 acres

50 acres

200 acres

100 m edge = 12 Pair

A 300 m edge = 2 Pair

100 m edge +16 Pair

A 300 m edge = 9 Pair

Edge Effect Simplified Food Web- Wytham Woods, England

Primary

Producers Herbs Trees/Shrubs Oaks Total Litter

Herbivores

Carnivores

Top

Carnivores

InsectsOther Leaf

Feeders

Winter

Moth

Earthworms

Fungi

Voles

Mice

Spiders

Parasites Owls Weasels Hyperparasites

Shrews

Moles

Beetles

Soil

ArthropdsTitmice

Cyzenis

90% of Energy

flows through

detritivore chain!

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A

C

B

D

Plants as part of wildlife diet

Preference by wildlife

• Preferred

• Second choice

• Starvation foods

Other Resources

Humboldt Field Research Institute and Eagle Hill Foundation , “Northeastern (& Southeastern) Naturalist”: http://www.eaglehill.us/programs/journals/nena/northeastern-naturalist.shtml

Natural Resources Conservation Services Programs for wildlife conservation: http://www.nrcs.usda.gov/

Natural Resources Conservation Services

Wildlife Habitat Incentive Program (WHIP): http://www.nrcs.usda.gov/programs/whip/

Natural Resources Conservation Services Pollinator Enhancement Activity (PLT01): http://www.nrcs.usda.gov/programs/new_csp/2010/ranking_period_two/jobsheet_pdfs/plt/10_R2_PLT01_Pollinator_Habitat_Establishment.pdf

Northern Prairie Wildlife Research Center: http://www.npwrc.usgs.gov

Patuxent Wildlife Research Center: http://www.pwrc.usgs.gov/aboutus/