Food Cover

What is habitat use?

• What animals are using in home range

• Home range is where they spend 95% of time

  • Home range is determined (in habitat use) by tracking collars

  • can also look at the 50% core area (bulk of time spent here)

• Habitat selection is use proportional to what’s available

  • important for wildlife biologists to know what animals are selecting for in habitat; what depth do fishes select, what forest areas do terrestrial animals select

  • EX: use GIS to see that home range is 25% forest, 50% agriculture, 15% Riparian, 10% urban

    • animal spends 30% of time in forest, 40% in agri., 20% Riparian, 10% urban… so what does animal select for?

      • selecting forest, avoiding ag., selecting Riparian (since they select it more often than it appears in habitat)

      • + and - chart

      • saw avoidance for ag. in bobcats

• Habitat preference is what an animal prefers

  • can’t tell from a human perspective

  • theoretically you can tell what a human prefers by being told, but can you really? the more options, the more a preference can be shown

  • so when limited options, preference is hard to determine since you’re just picking the lesser of 2 evils

  • deers selected Ponderosa Pine out West because it was the only thing there (Aspen gone, 5% compared to 95%)

Importance

• Food and cover is important

  • wildlife

  • wildlife managers

• Prescribed burn removes dead stuff, doubles shrub growth, gets rid of weeds, increase nutritional content

  • thin and burn

Food

• Energy

• Protein

• Macro and micronutrients

• Herbivores

  • quality is most important, not quantity

    • deers select for the best leaves since they have to eat a lot to feel full

  • a low of low quality forage

  • “starve” with full stomach without the right nutrients

• Carnivores

  • quantity most important, not quality

    • meat is meat

    • ambush predators who catch whatever they can

  • limited about of high quality prey

  • Can’t catch enough to survive

• Greenbrier

  • 24.7% CP

  • 87% digestible

  • 21g of protein per 100g

  • (7x more efficient than longleaf!)

• Longleaf Pine

  • 5% CP

  • 57% digestible

  • 3g of protein per 100g

• Hunting groups put out “mineral stumps” which are high-mineral concentrated leaves since the plant must increase concentration above-ground when roots below-ground are the same

• Most lands are overstocked with timber, need to cut down every 2 trees and open up canopy, so forest floor can grow

Energy

• Energy requirements are inversely related to body weight

  • ex: shrew needs 526 kcal/kg, brown bears needs only 28 kcal/kg

• Carbohydrates

  • small molecules—sugar (glucose, sucrose)

    • digests quickly

  • large molecules—cellulose, lignin

    • lignin part of the cell wall as plant matures

    • physical barrier to microbial enzymes

    • more lignin reduces quality of forage

    • a lot of energy, most animals can’t digest

• Fats

  • high in energy, but slow to digest

  • essential fatty acids—not used as fuel

Protein

• Amino acids building blocks of proteins

• Deer synthesize in gut from plant proteins

  • symbiotic bacteria

• Crude protein and digestible protein

• Herbivores

  • body maintenance 6%

  • 14% lactation

    • corn 2-8%

      • better to have natural forage than corn

    • average Frob 20-30%

    • see table 7-1 in book

Coevolution

• One-upmanship between predators and prey

• But also mutural dependency

  • seed dispersal

  • scatter hoarding

    • squirrels and acorns

• “Defenses” by plants

  • spines, chemicals

• Defenses by animals

  • coloration, speed

Specialized Feeding

• Specialized feeding

  • snail kite

  • crossbills

  • anteaters

• Not just about perfecting habitat, but food availability—prey abundance surveys (for animals that need a certain type of prey)

Generalist Feeding

• white-tailed deer (>100 plant species annually)

• coyote → eats shrews, moles, raccoons, rabbits, squirrels (small mammals), fruit, insects (grasshoppers, grubs—high in protein, water)

• bears

Soil Fertility

• Plants generally grow better on more fertile soils

• Best opportunity for wildlife management is on the best quality sites

• Nutritional Quality

  • good soils = poor soils

  • even though plants will have the same nutritional quality on both good and bad soil, but poorer soils will have less biomass (amount of nutrition)

• Amount (biomass) nutrition

  • good soils (more biomass) > poor soils (less biomass)

Bermann’s rule

• Bergmann’s rule

  • body size increases with latitidue

Antlers

• Where in the USA are large antlers?

  • fertile soils? yes, but not b/c of nutritional quality → biomass

Soil Fertility

• Fort Bragg buck

  • poor soils

  • available nutrition poor

  • 6.5+ years old

Nutrition

• Coprophagy

  • eat fecal matter

  • fairly common among herbivores

• Select forage with needed nutrients

• Affects reproduction

  • malnourished deer produce less milk

• Young herbivorous birds need insect proteins

• Over browsing

  • consumption exceed the plant’s ability to regenerate

• Shortages

  • animals can live a long time on limited food availability especially in winter

  • changed metabolic rate

    • hibernation (rodents, bears not true hibernators, beavers)

    • metabolic rate of northern deer reduced in winter

  • giant pandas

    • flowering cycle of bamboo can lead to starvation

• condition indices

  • kidney fat, weight/wing length, plumpness of fish (weight/standard)

Food Habits

• Food habits (diet)

  • determined by digestive tracts, scats, crops, owl pellets

• Preference

  • determination requires an “unlimited range” of choices

• Selection

  • choices are limited

• Selection = use relative to availability

• Varies seasonally

  • grouse in Lake States

    • summer and fall, they eat almost anything

    • in winter, male staminate flower buds of aspen

      • mature aspen winter cover

      • young aspen brood rearing cover

      • mid aged aspen breeding cover

        • drumming logs

Use, Selection, Preference

• Use = what an animal uses

• Selection = relationship between availability and use

  • 

• Preference = cannot determine - must have every possible choice

Deer Diet Composition

• Mostly browse/leaves and forbs

Food Management

• Food plots

  • first must understand limiting factors

    • Liebig’s law of the minimum — growth controlled by the scarcest resource

• Installing food plots is probably “busy fussing”

• Supplemental feeding? Baiting?

  • generally a bad idea

    • sustains a population that exceeds carrying capacity

      • beaver basin, MI example

    • Candy blocks for bears in eastern NC

    • Animals might not be able to adapt to it

    • Potential to spread disease

    • Change in behavior—bears in GSMNP

      • Costly

• Backyard bird feeders

  • same issues?

  • increased survival and productivity has been shown for resident species where winters are harsh

  • unintended consequences

    • nuisance species

    • disease

    • feral cats

Food Shortage Options

1. Do nothing

   1. population crash

2. Reduce population

   1. increase mortality, reduce natality

   2. hunting, poison, birth control

   3. Immunocontraception

3. Trap and relocate

   1. costs, merely relocated the problems, survival?

4. Artificial feeding

5. Habitat management

6. Combination of 2 and 5

What is more important?

• What drives habitat selection?

• 

Cover

• Provides protection from predators and weather

  • vary with function and season

• Shelter

  • animals adapted to microenvironment, which they can alter by behavior

    • beaver example

  • deeryard

    • reduced metabolism, limited food intake, shelter in cedar swamps most important

Shelter

• Behavior

  • emperor penguins huddle, quail roosts, bear dens, snake hibernacula, beaver lodges

  • woodcock wintering in eastern NC

    • row and furrow agriculture

    • wind chill less in furrows

• Not studied much

Concealment

• Protection from predators

• More horizontal cover is associated with more rabbit droppings

  • Young aspen overhead cover from avian predators

• Fawns in MD—tall warm-season grasses

• nests

  • vegetative structure, camouflage

    • careful when studying nesting

  • subnivean

    • underground burrows and under vegetation