Chapter 8 Integrated Pest Management
Pests, including insects, rodents, nuisance birds, and certain mammals, are common in zoos because of the ready availability of food, water, and shelter. Control of pests is a critical aspect of preventive medicine at zoological parks. Pests may be vectors or reservoirs of disease that may adversely affect zoo animals and guests. Pests may also significantly degrade buildings, exhibits, and the esthetic quality of the park. They have an economic impact by damaging facilities, preying on collection animals, introducing disease, and consuming animal diets. Developing a pest management program is key to controlling pests in a zoological setting and is required for licensed animal facilities (Animal Welfare Act; 7 U.S.C. s/s 2131 et seq [http://campusvet.wsu. edu/iacuc/pdfs/awapdf.pdf]).
The most successful vermin control strategies in zoological facilities include integrated pest management (IPM), which involves analysis of the pest and attempts to use the safest approach to control the population, in keeping with environmental concerns.5,26 IPM uses regular monitoring to determine if and when control measures are needed. This pest management approach takes into account the biology of the target pests and the effects of any control methods on the pests, animal collection, employees, and visitors to manipulate natural processes for maximal effectiveness.
The goal of IPM is to reduce pest numbers to an acceptable level through methods that are safe for a zoo’s animal collection and least disruptive to the park’s environment. A comprehensive program should define the scope and magnitude of the problem, identify appropriate expertise, define a safe and effective plan, implement the program, regularly reevaluate the results of the program, and make improvements when necessary. Communication among animal care staff, pest control staff, animal and facilities managers, and veterinary staff is essential to the success of an IPM program.5 The pest species is usually identified by animal care staff or guests. Animal care staff, managers, and pest control officers discuss how to use the most effective, least toxic, and appropriate control measures; plans are reviewed by management and approved with veterinary input prior to being implemented.
Indirect Suppression
Although each pest species varies in its preference for food, water, and shelter, preventing and decreasing access to these essentials has been shown to provide the best long-term effects with pest management. A study evaluating the efficacy of different pest management strategies has shown that mechanical alterations to buildings, restricting access to nutrients and shelter for pests, and education, in association with regular chemical treatments, is more effective than repeated pesticide application alone.17 This same observation has been supported by Collins and Powell,5 who described indirect suppression (e.g., modifying exhibits, changing human behavior, educating staff) as being the most important strategy for long-term pest control as part of IPM within a zoological park. Nonanimal areas, particularly those used for storage, are areas frequently underemphasized in a zoo’s IPM program, but are equally as important to maintain and inspect, because they often contribute to pest harborage.
Sanitation and maintenance guidelines as they pertain to the care and well-being of zoo animals have been established by the U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) through the Animal Welfare Act. The maintenance of an effective program for the control of insects, birds, and rodents in animal areas and the main commissary storage areas is the legal obligation of USDA-licensed facilities. USDA inspections identify areas of institutional noncompliance and encourage compliance through the education and cooperation of zoo personnel. Simulated USDA inspections in zoo units have proven to be helpful for achieving compliance with pest control goals through staff education.5
Direct Suppression
The direct suppression or mechanical control of pests varies based on the species and location of the infestation and should always include a multisystem approach to ensure the most effective pest management. Direct control measures of IPM often include: exclusion, baiting, repellents, trapping, removal, euthanasia, and relocation. Taxa-specific control options, including exclusion recommendations, chemical control measures, and natural remedies for specific species, are presented in Tables 8-1 and 8-2.
TABLE 8-1 Vertebrate Pest Control
| Species | Physical Control | Chemical Control |
|---|---|---|
| Rodents: mice (deer, harvest, house, meadow, white-footed mice, cotton), rat (Norway, roof, wood) | Exclusion: Remove food sources and shelter, identify entry sites (sprinkle nontoxic powder [flour, chalk, talcum] around suspect holes), plug active exit and entry sites (>0.6 cm with 18- to 22-gauge wire hardware cloth), maintain door sweeps on all exterior doors, screen drains, place guards along pipes and wires, prune trees and shrubs to maintain a gap of ≥1 m between foliage and ledges and rooftops, prune ground cover and shrubs along buildings to expose lower 45 cm of trunk.Trapping: Inside buildings, along edges; check traps twice daily (snap traps, live traps, glue boards), bait traps (peanut butter, cheese, cotton) before setting trigger. | Baiting Anticoagulants First generation: Warfarin Diphacinone Chlorophacinone Second generation: BrodifacoumBromadiolone Single-dose toxins Zinc phosphide Vitamin D3Outdoor Bait StationsProtectaRat DepotBait Safe |
| Ground squirrels, moles, gophers | See rodent exclusion methods. Prevent access to food. Trapping: Underground live traps | Baiting not recommended, high risk of secondary toxicity Repellents: moth balls/flakes (naphthalene), Bitrex, thiram, ammonium soaps applied to vegetation |
| Tree squirrels | See rodent exclusion methods. Exclusion: Use sheet metal bands on trees, close external openings to buildings, use plastic tubes on wires, set up squirrel-proof bird feeders. Live trapping | Repellents: moth balls/flakes (naphthalene), Ropel Spray, capsaicin, polybutenes |
| Rabbits | Netting, electric fencing, live traps, tree wrap | Repellents: Hinder Deer & Rabbit Repellent, National Scent, Ropel Spray, Green Screen, Getaway |
| Opossums and skunks | Exclusion, live trapping, and removal; seal off burrows (Safeguard, Tomahawk, Havahart) | Not recommended |
| Raccoons | Exclusion: Maintain roofs (replace loose shingles, repair holes near eaves of the roof), limit roof access (trim trees, shrubs), prevent access to chimneys (commercial spark arrestor cap of sheet metal and hardware cloth over top of chimney, heavy screen wire securely over opening); use garbage cans with tight-fitting lids. Live trapping: Bait traps (Safeguard, Tomahawk, Havahart) q48h (crisp bacon, fish, fresh vegetables, cat food, chicken parts and entrails, corn, sardines); set multiple traps in many locations, especially close to den; check traps twice a day; trap, release, relocate based on wildlife regulations; sterilization, culling | Not recommended |
| Bats | Exclusion and removal: One-way door over entry, exit holes; bat eviction valve; fine mesh (≤1.25 cm) over entry and exit sites; seal gaps of ≥0.6 × 3.8 cm and openings ≥1.6 × 2.2 cm; copper mesh hole filler; netting; bat, swallow, and woodpecker kits for home-made bat check valve; fill open spaces with fiberglass insulation; use sticky repellents around entry, exit site; supply a bat house for roosting. | Repellents: Moth flakes (naphthalene) |
| Carnivores: Bobcats, cats (feral, domestic), coyotes, dogs, foxes, mountain lions | Exclusion, trapping, and removal for small cats, dogs, and foxes | Immobilization through remote injection and removal for coyotes, dogs, and large cats |
| Deer | Buffer zones that extend ≥365 m from cover or woodlands; plant diversionary plots of alfalfa, clover; plant-resistant ornamental foliage; deer exclusion fencing; wire cylinder tree guards; reproductive control (PZP vaccine, surgical sterilization); cull via hunting | Chemical repellents: Human hair, hot sauce, predator scents, blood meal, egg solids (Deer Away) |
| Birds: Canada geese, crows, ducks, European starlings, egrets, herons, house sparrows, pigeons, raptors | Habitat modification: Prune trees; net off roosting sites and over exhibits (mesh <2-cm openings); eliminate overhangs and ledges from buildings; nest destruction every 10-14 days; mechanical repellents to prevent roosting (wire prongs, sheet metal spikes placed along ledges or under eaves). Live trap: Rotate sites (Tomahawk) Deterrents: Alarms and detonators (distress calls to deter Canada geese, electric shock, flashing light, reflective tape) Repellents: Balloons, gel, kites, sticky repellent, adhesive | Repellents: Ropel, Bird Proof Gel/Liquid, 4-The-Bird Repellent |
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