Identification and Management of Wildlife Damage

1. Identification and Management of Wildlife Damage Kurt C. VerCauteren, Richard A. Dolbeer, and Eric M. Gese

2. Wildlife Damage Management • Wildlife Damage in the US • Cost is ~ $22 billion annually • Control is important due to • Expanding human populations • Intensified land-use practices

3. Wildlife Damage Management Must Be . . . • Actions must be justified, environmentally safe, humane, and in the public interest • Based on sound economic, ecological, and sociological principles • Carried out as positive, necessary components of wildlife management programs

4. Four Principle Components (1) Problem definition • Species causing problem • Number of animals • Amount of loss • Nature of conflict (2) Ecology of the problem species (3) Management methods application • Develop an appropriate management strategy using (1) and (2) (4) Evaluation of management effort • Assess the results relative to cost and impact on target and non-target populations

5. Legal Requirements for Management • It is important to understand the laws regarding target and non-target species • Capture, possession, or killing of most mammals, reptiles, and amphibians is regulated by state or provincial laws • Federal regulations require that a depredation permit be obtained before most migratory birds can be captured, killed, possessed, or transported to control depredation

6. Examples of Damage by Birds

7. Examples of Control Techniques for Birds • Habitat Modification and Cultural Practices • Netting and Screening • Frightening Devices • Repellents • Toxicants and Capture Agents

8. Habitat Modification and Cultural Practices • Can be implemented to make roosting, loafing, or feeding sites less attractive • Lure crops may be used to control waterfowl or blackbirds. • Bird-resistant crops may also be used to limit losses

9. Plastic netting to protect crops Netting or wire screening may be used to exclude birds from building structures Building ledges can be angled 45o to deter perching Spikes and electric wires can be used to deter perching Overhead monofilament lines can be used to deter many bird species Proofing and Screening

10. Frightening Devices • Propane cannons • Pyrotechnics • Recorded alarm / distress calls • Flags, kites, and helium balloons • Strobe lights • Ultrasonic devices • No device is 100% effective • Birds quickly habituate

11. Repellents, Toxicants, and Capture Agents • Toxicants and capture agents require knowledge of the habits and food preferences of the target species • DRC-1339: used to control starlings, gulls • Avitrol: frightening agent used to control pigeons, gulls, house sparrows, starlings, blackbirds • Alpha-chloralose: used to capture waterfowl and pigeons • Repellents based on smell and taste are generally ineffective • Condition-aversive repellents are more effective • Produce illness or adverse physiological responses upon ingestion

12. Examples of Ungulate Damage

13. Repellents Fertility Control Examples of Control Techniques for Ungulates • Lethal control • Regulated hunting • Sharp shooting • Habitat and Food Modification • Fencing and Barriers • Frightening and Hazing • Dogs as Deterrents

14. Lethal Control • Regulated managed hunting is the most practical and effective method of management • Is the most ecologically, socially, and fiscally responsible method

15. Habitat and Food Modification • Select unpalatable/ resistant plants • Reduce permanent cover • Harvest crops as soon as ripe • Lure crops / Baiting • In some situations these may actually increase local damage

16. Exclusion: Fencing and Barriers • Fencing can be a long-term, nonlethal control method. Fencing provides protection by acting as a physical barrier and/or psychological barrier • Variables to consider: level of protection desired, seasonality of the resource being protected, physical ability of the target species, motivation to breach, behavioral characteristics, cost, longevity of materials, potential negative effects

17. Frightening and Hazing • Ungulates habituate quickly • Many marketed devices do not work • Devices that target multiple senses are the most efficacious • Persistent hazing can be effective • Dogs may be used as deterrents

18. Repellents • Limited effectiveness • Odor repellents: designed to repel animals, and either mimic predator odors or are repugnant • Contact repellents are applied directly to the target resources and change the hedonic quality of the item, and/or cause illness (aversive conditioning) • Systemic repellents: are incorporated into plants naturally, by supplementation, or genetic manipulation

19. Fertility Control • Wildlife contraceptives have the potential to be complimentary management tools, however; it is unlikely that fertility control will become a stand-alone management strategy • Methods include chemosterilants, intrauterine devices, immunocontraceptives, and surgery • Recent developments include single-shot fertility control methods, orally delivered contraceptives, viral- or bacterial-vectored delivery methods

20. Examples of Damage by Rodents and Small Mammals

21. Rodents and Other Small Mammals • Damage is frequently difficult to measure; most species are nocturnal and not easily observed. Characteristics of damage may provide clues. Quantification of damage is often made by comparing the damaged site with an undamaged area, then converting the losses to dollars. • Damage to plants may be generally grouped as: • Root damage • Trunk debarking • Stem & branch cutting • Needle clipping • Debudding

22. Biological Management Fertility Control Repellents Fumigants Toxicants Examples of Control Techniques • Habitat Modification • Cultural Practices • Exclusion • Frightening Devices • Removal

23. Habitat Modification and Cultural Practices • Elimination of food and shelter • Remove brush, debris, woodpiles, garbage, refuse, tall vegetation • Mechanical devices • Provision of alternative foods • Remove insect and invertebrate food supplies

24. Exclusion • Installation of barriers that prevent access to structures or areas, or eliminate contact with specific objects • “Rodent proofing”

25. Biological Management and Fertility Control • Biological Management: • Introduction of agents of disease and predatory species. Be careful, historically has led to dire unintended consequences (e.g., mongoose). • Fertility Control: • In time may be an effective supplemental tool. Oral and immunological agents are being developed as are viral-vectored immunocontraceptives.

26. Repellents • Repellents are most effective when applied to foods • Several compounds are registered for use, however; efficacy data is often lacking • Chemical repellents include: • Sensory repellents • Semiochemical odors • Taste avoidance behavior compounds

27. Fumigants and Toxicants • Fumigants are used for lethal control of burrowing mammals. Examples include smoke-producing gas cartridges, aluminum phosphide, choloropicrin, and methyl bromide • Toxicants are labor and cost efficient, and are the most commonly used method of control. Potential hazards to non-target wildlife must be considered prior to use. Two types of toxicants are commonly used • Anit-coagulants • Non-anti-coagulants

28. Removal • Foothold traps are commonly used to trap beaver, muskrat, and nutria; smaller sizes are used to capture small mammals. Body gripping traps are used for beaver, muskrat, nutria, moles and pocket gophers. Snap traps are typically used to control rats and mice. Snares may be used to capture or kill beaver, rabbits, and other animals. Shooting may be used to selectively eliminate some pest mammals Live traps are often used to capture mammals of all sizes

29. Examples of Damage by Carnivores and Other Mammalian Predators

30. Carnivores and Other Mammalian Predators • Livestock depredation has been a concern to livestock producers for centuries. Accurate assessment of a predation event requires careful observation. Signs of predation and the possible predator involved should be searched for on the prey item and around the kill site. Scavenging should not be confused with predation.

31. Financial Incentives Livestock Protection Collars M-44s Aerial Hunting Trapping Calling and Shooting Hunting with hounds Snares Examples of Control Techniquesfor Carnivores • Livestock Husbandry Practices • Guard Dogs • Guard Llamas • Guard Donkeys • Fencing and Barriers • Frightening Devices • Repellents and Aversive Conditioning • Reproductive Interference • Relocation

32. Livestock Husbandry Practices • Confine or concentrate herds • Use of herders • Shed lambing/ calving • Remove dead livestock • Synchronized birthing • House young livestock in areas with little cover, and in proximity to humans

33. Guard Dogs • Studies investigating the efficacy of guard dogs have shown the dogs to be effective in some situations. Efficacy decreases in areas of thick cover, or when large flocks are dispersed over rough terrain • Use of guard dogs precludes the use of other control devices such as traps, snares, or toxicants

34. Llamas can be a practical and effective technique to deter predators (especially coyotes and dogs) Guard Llamas and Guard Donkeys • Donkeys may also be used as livestock guardians against coyotes and dogs. They are most effective in small, fenced pastures

35. Fencing and Barriers • Fencing is best suited for protecting small areas. Standard fencing will not always deter predators. Adding electric fence along, or above the fence improves efficacy, however; the effect of • the electric fence on the • species being protected • must be considered. • Burying wire mesh • helps prevent predators • from digging into an area. • Barriers include flagging, exclosures, electric fence, nest screen, moats.

36. Frightening Devices Lights Distress calls Loud noises Scarecrows Plastic streamers Propane cannons Radio Activated Guard (RAG) device Motion Activated Guard (MAG) device All of these devices provide temporary relief only. Changing the location, pattern of disruption, or combining techniques may prolong the success. Light may be the most important component of the frightening device.

37. Repellents There are no commercially available repellents that effectively deter predation Aversive conditioning Use of lithium chloride may reduce consumption of prey, but does not deter predation in coyotes May be effective in “teaching” black bears to fear and avoid humans Repellents and Aversive Conditioning

38. Reproductive Interference and Relocation of Problem Animals Relocation • Relocation programs have had limited success with bears and wolves • Relocation efforts are expensive, but are considered worthwhile and necessary in the management of endangered species Reproductive Interference • Presently there are no species-specific reproductive control measures, although use of immunocontraceptive agents has been investigated. • Vasectomization of coyotes and wolves has been investigated as well.

39. Financial Incentives • Assessment of local economic and ecologic conditions should be performed before implementing a compensation program. Incentives may be best realized if tied to conservation outcomes • “Predator Friendly Products” which come from ranches that do not kill predators • Problems with compensation programs: • Producers feel they don’t receive fair market value • Compensation is not paid for “missing” animals • Compensation doesn’t encourage correction of poor management practices

40. Livestock Protection Collar • The collar fits around the neck of lambs and kid goats, and contains bladders filled with 1080 (an acute toxicant). It is is designed to kill coyotes when they puncture a bladder during a predatory attack. • Advantage: • Selective removal of problem animals • Disadvantage: • Cost & labor • Accidental puncture of the bladders

41. M-44 • A mechanical device that injects sodium cyanide into the mouth of an animal when it bites/pulls on the device • M-44 is registered and authorized by different agencies depending on the country of use for coyotes, foxes, and feral dogs • Disadvantages: • Not species specific • Does not always remove the problem animal • Numerous use restrictions

42. Aerial Hunting • Fixed- and rotary-wing aircraft are commonly used in control programs for wolves, coyotes, bobcats, and foxes. Hunting is most effective with snow cover • Federal law requires each state where aerial hunting is allowed to issue aerial hunting permits. Some states also require low-level flying waivers.

43. Traps • Cage traps can be used to capture predators of all sizes • Foothold traps are more effective and available in various sizes • Most states have regulations on types of traps, baits, sets, and trap visitation schedules. Some states no longer allow foothold traps. Consult state and local regulations prior to conducting any trapping activity

44. Calling and Shooting • Can be a selective means to control coyotes, bobcats, and foxes. Commercial and recorded calls mimic the sound of a rabbit in distress or a pup in distress. Morning and late afternoon are the most effective times to employ calling, although calling at night and using a spotlight (where legal) may be effective as well.

45. Hunting dogs are used for lethal control. State and local laws should be consulted prior to pursuing carnivors with dogs. Two types of dogs are commonly used Hunting Hounds • Sight hounds • Greyhound • Most effective in open terrain • Trail hounds • Redbone, Walker, Bluetick, Black & Tan • Hunt by scent in packs

46. Snares • Constructed of wire or cable looped through a locking device that allows the snare to tighten • Two types: • Body snares are used primarily on coyotes and foxes, in areas where the predator crawls under a fence, at a den entrance, or in a narrow passageway • Spring activated foot snares are used to capture large predators

47. SUMMARY • Wildlife Damage Management is an increasingly important part of the wildlife profession because of expanding human populations, intensified land-use practices, increasing prominence of wildlife vectoring disease, and other reasons. • Many species at one time or another require management actions to reduce conflicts with people, livestock, or other wildlife species. • There are few “silver bullet” easy remedies. • Integrated Wildlife Damage Management Strategies, using a variety of techniques to dynamically target problem individuals or species are usually preferred and most effective for long-term management.