Food shortage appears to be the chief natural factor limiting the numbers of many birds, of various carnivorous and herbivorous mammals, of many larger

Food shortage appears to be the chief natural factor limiting the numbers of many birds, of various carnivorous and herbivorous mammals, of many larger marine fish, and of certain predatory insects

D. Lack

Food, Water, & Nutrition

• What are the relationships between nutrition and wildlife populations?

• What are food components and how does understanding them help us as a wildlife biologist?


• What is the differences between food use, food digestibility, food availability, & food selection; what affects these thing’s, and how can I use this information to manage wildlife?

• How do wildlife get water, and how much water do wildlife need?

• Who cares?


• Nutrition affects condition, mortality, & reproduction– Population Dynamics (i.e., N)

• Food & water = Welfare or Decimating Factors?


High Nutrition Low Nutrition

Does examined 27 22

Does not bred 0 2

Fawns produced 47 21

Litters (1:2:3 fawns) 2:21:1 17:2:0

Fawns per doe 1.74 0.95

% male fawns 36 69

• White-tailed deer (New York; Verme 1965)

• Florida?


Compared to birds eating a “normal” diet (%)

Species Diet Body mass Ovary massEgg

productionEgg

mass

Northern Bobwhite Low E 0.81 0.25 0.12 0.99

Low P 0.89 0.73 0.71 0.94

Low E & P 0.80 0.17 0.10 0.97

Scaled Quail Low E 0.99 0.42 0.26 0.96

Low P 1.00 1.00 1.00 0.99

Low E & P 0.85 0.21 0.30 1.00Giuliano et al. (1996)

Jeff Vanuga, USDA NRCS


• Food Components– Energy– Proteins – Carbohydrates– Fats– Minerals (Nutrients)– Vitamins

– Water

• Energy– Season– Activity – Size matters– Species

– Thermal neutral zone

– Homeotherms v. poikilotherms– Endotherm v. ectotherm

Food, Water, & NutritionHomeotherms

0

50

100

0 0.5 1 1.5

Body Mass (Kg)

BM

R (

Kca

l/day

)

0

2

4

6

8

10

12

14

Rel

. BM

R (

Kca

l/day

/100

g b

od

y m

ass)


• Energy– Content (gross): Fats > Proteins > Carbohydrates

– Utilization: Carbohydrates > Fats > Proteins

– Food v. stored• Mammals > birds > herps


• Energy

(W.W. Mautz/Wildlife Management Institute 1978)


• Energy

– Species-specific

Gross Energy Digestible Energy

Energy Lostin Feces

Metabolizable Energy

Energy Lostin Urine and Methane

Net Energy

Energy LostIn Work of Digestion


• Carbohydrates– 3.9-4.2 kcal/g– Cellulose, starches, sugars– Plants*– Availability/digestibility


• Fats (and oils)– 9.5 kcal/g– Meat and some seeds– Availability/digestibility


• Protein– 5.7 kcal/g– Amino acids*– Meat and legumes– Availability/digestibility


• Minerals (Nutrients)

– Micro v. macro• 0.01% of body mass

– Licks


• Vitamins– Essential in small amounts

– Coprophagy


• Proper nutrition– Diverse diet

– Carnivore v. herbivore• Energy• Other components• Parts of foods not the same• Selectivity

• Protein & vitamin issues for herbivores


Bolen, Eric G.; Robinson, William, Wildlife Ecology and Management, 5th Edition, ©2003. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

Food

Energy (Kcal/100 g)

Protein (%)

Fat

(%)

Carbo’s (%)

Grass 220 13 6 73

Jack pine needles 524 9 12 77

White cedar twigs & leaves 237 3 4 91

Snails 219 52 1 0

Crabs 170 33 2 9

Insects 374 56 4 24

Fish 426 76 4 0

Bird eggs 430 38 31 0

Birds 446 57 24 0

Mammals 448 89 10 0

(From Bolen & Robinson 2003)


• Diet– Species– Sex– Age– Season– Year


• Understanding wildlife nutrition– Food use– Food digestibility– Food availability– Food selection*


• Food use– Carnivores v. herbivores

– Feeding rates• Predation & foraging behavior

– Bobwhite & supplemental feeding example– Large carnivores in Africa example

(U.S Fish & Wildlife Service)



• Food use– Quality v. quantity

• Species– Herbivore v. carnivore

• Season– e.g., Spring or after fire green-up

• Part of organism– e.g., seed v. stem


Bolen, Eric G.; Robinson, William, Wildlife Ecology and Management, 5th Edition, ©2003. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

Food

Energy (Kcal/100 g)

Protein (%)

Fat

(%)

Carbo’s (%)

Grass 220 13 6 73

Jack pine needles 524 9 12 77

White cedar twigs & leaves 237 3 4 91

Snails 219 52 1 0

Crabs 170 33 2 9

Insects 374 56 4 24

Fish 426 76 4 0

Bird eggs 430 38 31 0

Birds 446 57 24 0

Mammals 448 89 10 0

(From Bolen & Robinson 2003)


• Food use– Habitat effects

• Especially herbivores– K

Food, Water, & Nutrition• Food digestibility

– GI tract length & passage rates important– Artificial feeding problems

Bird Mammals & Herps Ruminant Mammal

Mouth

Crop

Proventriculus

Ceca

Gizzard

Intestine

Cloaca

Stomach

Vent

Rumen

Omasum

Reticulum

Rectum

Esophagus

EsophagusSmall Intestine

Large Intestine

Anus

Cecum

Abomasum

Rumen

Food, Water, & Nutrition• Food (& components) availability

– Quantity– Accessibility– Digestibility

• Plant defenses• Hard animal parts

– Effects on movements & distribution• Native• Food plots• Supplemental feeding



• Food selection– Use relative to availability

– A limiting factor/link

Food % use % available Selection

A 60 80 -

B 10 10 0

C 30 5 +

D 0 5 -


• Jaguar feeding ecology: the distribution of predator & prey through time & space– A case study


• Water– Digestion, metabolism, excretion, & cooling– Cover

USDA Photo: Tim McCabe


• Water– Sources

• Free water– Ponds, puddles, dew, etc.

• Foods– Seeds: 2-3%– Animal tissue & succulent plants: up to 70%

• Metabolism (metabolic water)– Fats: 1.07 ml/g– Proteins: 0.40 ml/g– Carbohydrates: 0.56 ml/g


• Water– Size, sex, age, & season– Adaptations– Effects on distribution

USDA Photo: Tim McCabe


• Effects on condition– Survival & repro.

• N

– Limiting season• Prior seasons

– Reserves

– Too fat?


Sliding down a brushy hillside


• Habitat management– Habitat components in relation to conditions

• Food, cover, water, & space

• So what!

Cover is a magic word in wildlife management. It is, indeed, often a magic wand with which wild animals and birds are made to populate places formerly uninhabitable. …It seems desirable that we should seek to analyze the complex nature of cover more carefully.

C. Elton

Cover

• What is cover?

• What types of cover are there?

• What factors affect cover selection?

• How do wildlife use cover differently?

• What factors affect cover quality & availability?

• Who cares?

Cover

• Cover v. habitat

• Covert

• Any structural resource of the environment that enhances reproduction and/or survival of wildlife by providing for any of the natural functions of the species (Bailey 1984)

– A place

• Cover = Welfare or Decimating Factor?

Cover

• Shelter for wildlife that consists of vegetation and topographic features that provide places to feed, hide, sleep, play, and raise young (Leopold 1933)

– Artificial structures

Chris Schnepf, University of Idaho, www.forestryimages.org

Cover

• Recognizing wildlife adaptations to cover

• Management

(U.S Fish & Wildlife Service)(U.S Fish & Wildlife Service)

Cover

• Multi-dimensional & 360◦

– Movements, shelter, & visibility

Cover

• Types & functions of cover– Shelter & concealment

• Winter• Refuge• Loafing/resting• Nesting• Breeding• Roasting• Thermal• Escape• Bedding/roosting• Feeding• Traveling

(NOAA Photo)

img5.travelblog.org

← Leopold’s “Special Factors”

Cover

• Ecological traps

Chris Schnepf, University of Idaho

Cover


Cover

• Generalists v. specialists

(U.S Fish & Wildlife Service)(U.S Fish & Wildlife Service)

Cover

• Vegetation: structure v. species

(U.S Fish & Wildlife Service) (U.S Fish & Wildlife Service)

Cover

David Shorthouse, University of Alberta

Paul Bolstad, University of Minnesota


• Deer yards– Limiting type– Snow, wind, & temperature– Food

– Limiting factor/link– The brushy hillside

Scott Bauer, USDA ARS

Cover

• What affects cover requirements?– Species– Function– Season– Age– Predation pressure– Pests– Weather– Region


Paul Bolstad, University of Minnesota

Cover

• Selection v. use v. availability

• Availability & management– Land-use– Succession

• So what!

Documents

Food shortage appears to be the chief natural factor limiting the numbers of many birds, of various carnivorous and herbivorous mammals, of many larger