Predators, Predation, & Predator Control

Bruce D. Leopold, Mississippi State University

Historical Perspective

• “Harmony with the land is like harmony with a friend, you cannot cherish his right hand and chop off his left. That is to say, you can’t love game and hate predators, the land is one organism.”

Historical Perspective

Predator Control Under Scrutiny

• Leopold Report (A. Starker)- 1964

• Cain Report - 1972

• Nixon (by Executive Order) stopped use of all poisons on federal lands or use by federal agencies to control predators

Trends Regarding Furbearing Predators

Possible Effects????

Before History Repeats Itself

?

Predators- Their Value

• A natural component of the ecosystem, often aiding in maintaining stability

• Often remove sick and injured individuals from the population

• Serve to keep animals “wild and wary”• Often regulate prey populations, many of these

prey populations are equally harmful to game animals

• Are valuable as sport animals

Predators- Societal ValuesSurvey of 1500 households

• have a right to exist• should be reintroduced to former ranges• do need to be managed, but with conditions• should not be hunted or trapped unconditionally• are not the cause of game population declines• play an important role to maintain balanced

natural systems• ==> They do support predator management!!!

Before Biologists “Jump into” Predator Control, They Need to

Consider Many Factors

Prey Predator

Animal Welfare Issues

• Animal Welfare Act & Amendments– Recently to include birds and rodents

• University IACUCs• Federal Funds and State Agencies (PR & DJ)• Initiatives to stop trapping and hunting

Must Be Careful of the Message

• Kill predators so that we have more game to harvest

• NWTF- Resolution- Not to Use Predator Control to enhance single species

• SE Section TWS- Resolution- Not to Use Predator Control to enhance single species

Management activities conducive to predators

• Logging roads/Access roads = Travel Corridors• Food plots =Concentrating prey & Predictability• Maintain early successional stages = Food base• Small management units = Increased efficiency

Identifying the True “Culprit”

Decimating versus Limiting FactorsNest Losses

• Massachusetts- 22%• Alabama: 85%• Kentucky: 1975- 55%

1978- 80%• Texas: 1972- 61%

1980- 56%

1987- 100%

Prey Adaptations- CoevolutionThe Wild Turkey

• Large body size

• Long-lived

• Roost in trees

• Form flocks

• Large clutch sizes

• Prefer open habitats

• Hen moves great distances when disturbed

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With PredatorControl

Without PredatorControl

Density-dependent ResponsesStudy in Texas and Coyote

• With intensive control: litter size- 6.56

• With no control: litter size- 3.65

• Well nourished coyote- from 10-12 pups

Interactions

• Coyote in Texas- w/ control, less rodent richness and diversity

• In SE US, coyote versus red fox

• Prairie- wolf versus meso-carnivores (raccoons, fox, skunk)

Predator ControlWhen is it warranted?The Wildlife Society

• When introducing a species to former habitat• Endangered/threatened species• Man-induced disruption

Problems identified with Predator Control

• Coyote- requires 75% reduction in population to observe a change in population status

• Must be intensive first 3-4 years• Can not stop• Can not be haphazard• Not cost-effective

Past Research ResultsPredator control will enhance game

populations

• White-tailed deer

• Wild turkey

• Pheasant

• Waterfowl

• Northern bobwhite

Problem is: in every study, cost of the “extra” animals was excessive

Possible solutionsHabitat manipulations

• Pronghorn and Coyote- Utah

• White-tailed deer and Coyote- Texas

Protocol for Predator Control• What are the management goals and thus management objectives for the prey

(game animal)? Are they reasonable and biologically sound?

• Has predation been identified as the ultimate mortality factor rather than a proximate factor?

• Has the predator species been identified correctly? Has appropriate Aevidence@ been collected and reliably identified (tracks, photos, sign on carcasses or eggs, etc.)

• Have extrinsic, contributing factors been examined throughly (habitat conditions, weather effects, land management activities) that may have, on the short-time, caused an imbalance in predator and/or prey species abundance(s)?

• Has the target predator species role within the system been evaluated thoroughly to ensure that the control operation may not further disrupt existing balances?

Protocol for Predator Control

• Have alternatives to active predator removal been examined based on evaluation conducted previously?– can habitat manipulation achieve desired goals?– can subtle changes in current land management be implemented?– can more “desirable” predator species be enhanced to counter “more detrimental

species”? [Note: enhanced can simply mean to cease trapping that predator species (e.g., coyote versus red fox)]

• Clearly define the objectives of the predator management program– What is the desired population response (e.g., density) of the prey (game animal)?– What is the desired percentage reduction in the target predator population?– What monitoring program(s) will be implemented to monitor response of prey species and target

predator species?

Protocol for Predator Control• Ensure that Best Management Practices (BMPs) for trapping (based on draft BMPs

under development) are adhered to. These include – appropriate traps that minimize injury to animal, – appropriate frequency of trap-line checking, – maintaining a trap-line size consistent with available resources, – capture of non-target species is monitored and minimized. If excessive, trapping procedures

should be reevaluated and modified, and– appropriate euthanasia procedure(s) for animals are implemented.

• Have societal beliefs (especially local and regional) been examined and considered? – if potential problems are identified, develop a concise response that provides empirically-based

data, program objectives, and target species.– all staff should provide a consistent response when inquiries are made about the predator

management program, or inquires should be redirected to one individual

Protocol for Predator Control

• Inappropriate behavior by staff should not be tolerated. Deviation from selected harvesting protocols and objectives should be stopped immediately.

• Carcasses should be disposed of discretely or used appropriately (food, museum displays, etc.).

Questions??