Proceedings of the Fourteenth Vertebrate Pest Conference 1990

USE OF ALPHA-CHLORALOSE TO REMOVE WATERFOWL FROM NUISANCE AND DAMAGE SITUATIONS

Paul P. Woronecki et al. — Thu, 08 Feb 2007 14:28:58 PST

From 1988 through early 1990 alpha-chloralose (A-C) was successfully used in the United States to immobilize and remove 70 Canada Geese (Branta canadensis), 315 mallard, domestic and hybrid ducks (Anas platyrhynchos), and 348 coots (Fulica Americana) from 17 commercial and residential sites including golf courses, pools, and ponds. Field trials and baiting techniques with bread and corn are described. The optimum dose of A-C for geese, ducks, and coots, using orally administered bread and corn baits, was about 20-30 mg/kg. We are currently pursuing registration of A-C as a bird control chemical with the U.S. Food and Drug Administration.

WARFARIN RESISTANCE OF Rattus tiomanicus IN OIL PALMS IN MALAYSIA AND THE ASSOCIATED INCREASE OF Rattus diardii

B.J. Wood et al. — Thu, 08 Feb 2007 12:01:35 PST

Rattus tiomanicus is a serious pest of oil palm plantations in Peninsular Malaysia, feeding on the ripening fruit. R. diardii is a rat of human habitations and has been only an occasional field species, presumably because it cannot compete with better adapted species. A widely used control for R. tiomanicus of proven effectiveness uses maize-based baits containing warfarin at 0.05% in 2 cm3 (14.5 g) wax-bound cubes. These are applied in campaigns at one per palm, replaced on 4 daily rounds, until acceptance has declined to 20%. This "standard method" is applied at about 6-month intervals, and rat populations remain low. In the early 1980s resistance to warfarin began in R. tiomanicus, and from about the same time R. diardii was found more often in oil palms, apparently in the same localities.

This review is of studies of these phenomena. Rat population studies by mark, release, recapture (MRR) confirmed that warfarin baiting was failing against R. tiomanicus, or required prolonged application, whereas second-generation anticoagulants (brodifacoum, bromadiolone, and flocoumafen) were effective. Physiological resistance was confirmed in the laboratory. Direct substitution of second-generation compounds increased the cost of control considerably, and ways to reduce costs were investigated. Smaller bait size presented problems in monitoring bait acceptance, and longer intervals between replacements did not reduce consumption. Half the active ingredient concentration had some promise, but a first-round application of one bait per two palms was most practicable. Bromadiolone baits at 0.005% are now used at half density of one bait per two palms on the first application in areas of warfarin resistance.

Where the problem was first noted, rat populations were compared in areas with and without continued baiting. In an 81-ha plot left unbaited, R. diardii gradually increased and replaced R. tiomanicus during 1982-84. R. diardii then remained predominant until 1989. In the baited plot, once bromadiolone was used (from early 1984) both species were controlled. It is postulated that R. diardii became able to out-compete R. tiomanicus because the genotype of the latter had somehow been weakened in the rapid selection for warfarin resistance.

RANCHER USE OF LIVESTOCK PROTECTION COLLARS IN TEXAS

Murray T. Walton — Thu, 08 Feb 2007 11:56:04 PST

With U.S. Environmental Protection Agency's approval of certification and training of sodium monofluoroacetate (Compound 1080) Livestock Protection Collar applicators by the Texas Department of Agriculture in April 1988, use of collars by ranchers was made possible. This paper presents data from 1988 and 1989 on use of Livestock Protection Collars to protect domestic sheep and goats subject to coyote (Canis latrans) predation. Information concerning coyote puncture of collars, loss of collars to other factors, and targeting strategies used by ranchers are discussed. Success of collar use is compared to other predator control methods used by ranchers.

A COMPARISON OF SEVERAL POCKET GOPHER BAITS IN THE FIELD

Paul Vossen et al. — Thu, 08 Feb 2007 11:56:03 PST

Two field trials were conducted to determine the effectiveness of anticoagulant baits in pocket gopher (Thomomys bottae) control. In the first trial, burrow systems were baited once with chlorophacinone 0.005% on rolled oats and embedded in paraffin to form a wax block. The systems were arranged in a one system-wide line bordering a clean vineyard. Infestation of the vineyard was prevented for 2 months; after that, gophers did bypass the barrier of treated systems and entered the vineyard.

In the second trial two anticoagulant baits, chlorophacinone 0.005% on rolled oats and embedded in paraffin, and diphacinone 0.0052% on various grains and embedded in paraffin, were compared to strychnine-treated 0.29% whole wheat grain bait. Fifteen individual gopher systems were baited in each of three replications and monitored for 8-½ months. Both of the anticoagulant paraffin block-type baits achieved significantly greater long-term gopher control than the strychnine-treated loose grain bait.

ROAMING, STRAY, AND FERAL DOMESTIC CATS AND DOGS AS WILDLIFE PROBLEMS

Bessel D. Van't Woudt — Thu, 08 Feb 2007 11:52:46 PST

From several centers of domestication, cats and dogs have become the near-ubiquitous companion of man. Their dependence on man is such that when abandoned in a rural environment most succumb to malnutrition in combination with predation, diseases, parasites, and exposure. Where not subject to predation and where native or introduced prey is adequate, some survive to form feral populations. This applies on oceanic islands, in Australia and New Zealand. Elsewhere, as far as is known today, requirements for survival are met with in parts of the U.S. and Europe only, in remote wilderness areas in the case of dogs, and more widespread, with a tendency to fall back on surplus and waste products of man during hard times in the wild, in the case of cats. Where vermin populations, such as those of rabbits, rats and mice are dense, cats provide inadequate control; they can be useful in keeping small vermin populations small. Away from oceanic islands and desert areas, where their impact on native animals can be disastrous, this makes them sufficiently useful for damage to wildlife (notably to lizards, small marsupials and some birds) to be outweighed, without providing a clear-cut case for a need for control of either roaming, stray or feral cats in rural areas. On the other hand, dogs are potentially destructive animals, whether roaming, stray, or feral; they demand strict control.

RODENT DAMAGE TO HAWAIIAN SUGARCANE

Mark E. Tobin et al. — Thu, 08 Feb 2007 11:50:46 PST

Rattus norvegicus, R. exulans, and R. rattus cause extensive damage to Hawaiian sugarcane. This paper gives an overview of the problem and briefly summarizes the history of rodent control on Hawaiian sugarcane plantations. Current baiting practices with zinc phosphide may favor the proliferation of R. norvegicus, and more effective control methods are needed for this species. A cooperative research and development program by the Denver Wildlife Research Center and the nonprofit Hawaiian Sugar Planters' Association is described.

ANIMAL WELFARE AND THE CONTROL OF VERTEBRATES

Harry V. Thompson — Thu, 08 Feb 2007 11:50:44 PST

The relationships between man and other animals have attracted increased attention and some controversy in recent years. Their importance in biomedical research, farming, and wildlife control are discussed in the United Kingdom context.

RODENTICIDE ECOTOXICOLOGY: SYSTEMS ANALYSIS AND SIMULATION

R.H. Smith et al. — Thu, 08 Feb 2007 11:47:38 PST

Exposure, as well as toxicity, determines whether rodenticides present real environmental hazards to nontarget animals. In order to combine exposure and toxicity, a compartment model is proposed which distinguishes transfer processes from accumulation of residues. The published literature relevant to the model is analyzed, and some important gaps in knowledge are highlighted. Simple sub-models of rat feeding behavior and mortality are combined into a simulation model which generates data on both efficacy of control and build-up of residues in live rats and carcasses. The roles of feeding parameters (e.g., palatability, availability of alternative food) as well as toxicity are emphasized by the simulation results.

ITS A FACT! ITS A PHACT!

Harlan R. Shuhler — Thu, 08 Feb 2007 11:47:37 PST

To reduce the costs of providing development assistance in agriculture to the people in the Developing Countries, an international "Post-Harvest Agriculture Computer Teleconference" has been available now for more than 15 months. Suitably supplemented with electronic computer communications networks and their E-mail, these tools allow relatively inexpensive assistance. This combination offers many advantages to the organizations offering assistance and those needing help.

AN EVALUATION OF FENCING TO EXCLUDE POCKET GOPHERS FROM EXPERIMENTAL PLOTS

Terrell P. Salmon et al. — Thu, 08 Feb 2007 11:43:44 PST

We evaluated the ability of underground fencing to exclude pocket gophers (Thomomys bottae) from experimental plots planted with alfalfa. Fencing extending 61 cm below and 91 cm aboveground, with a 15.2-cm lip bent 90 degrees inward at the bottom, did not prevent marked and unmarked gophers from escaping, invading, or moving among six adjacent plots. Complete underground screening, in combination with gopher control, may be the only technique which ensures the complete exclusion of gophers from experimental and ornamental plots.

RABIES CONTROL FOR URBAN FOXES, SKUNKS, AND RACCOONS

Richard C. Rosatte et al. — Thu, 08 Feb 2007 11:41:50 PST

Rabies is currently enzootic in many cities of southern Ontario. The Ministry of Natural Resources is utilizing two different tactics for the control of rabies in urban wildlife rabies vectors-oral immunization with baits (foxes) and vaccination by injection following live-capture (skunks and raccoons). Between 47 and 79% of the skunks and 61 and 76% of the raccoons were captured and vaccinated (Imrab) in a 60-km2 urban area of Metropolitan Toronto during 1987, 1989. Only three cases of rabies in skunks have been reported since control began in 1987. Population increases of 120% for skunks and 40% for raccoons were noted since the rabies control program was initiated. Densities for raccoons and skunks in urban habitat were found to be as high as 56 and 36 per km2, respectively. An estimated 56% of the foxes in Metropolitan Toronto were reached with rabies vaccine baits following distribution throughout the ravine systems and at fox pup-rearing den sites. To our knowledge, this is the first documentation of the use of a live-virus rabies vaccine for the control of fox rabies in a large metropolitan environment.

KEYNOTE ADDRESS--THOUGHTS ON THE FUTURE OF VERTEBRATE PEST MANAGEMENT

Russell F. Reidinger Jr. — Thu, 08 Feb 2007 11:39:38 PST

I greatly appreciated the invitation to attend this Conference, and to share some thoughts on the future of vertebrate pest management in the form of a Keynote Address.

In making the presentation, I will dwell mostly on a single document. This document is entitled “Strategic Plan for Animal Damage Control,” and became available in December 1989, from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS).

The document is one of the products from a strategic planning process that began in APHIS about 2 years ago, and continues today. The process began at the highest level of organization of APHIS itself, and that effort resulted in its own document. The process then continued with each of the eleven organizational units of APHIS. The federal operational Animal Damage Control (ADC) program is one of those units, and the referenced document is the product of their strategic planning effort. The Denver Wildlife Research Center (DWRC), familiar to many of you as the major federal research program in animal damage control, is part of the Science and Technology (S&T) unit of APHIS, and not organizationally part of ADC. Just like ADC, S&T also completed strategic planning, the product of which was a similar-looking document. In my opinion, the document is a good one and will serve a useful function for the S&T unit. However, it is also more broadly oriented than vertebrate pest management alone, and, because the ADC document is more tightly focused and can serve as well as a basis for discussion of the federal research program in vertebrate pest management, I have chosen to highlight the ADC document. I will digress from its contents slightly only in discussing the research aspects of vertebrate pest management.

THE STATUS OF LINES IN BIRD DAMAGE CONTROL–A REVIEW

Patricia A. Pochop et al. — Thu, 08 Feb 2007 11:37:48 PST

One technique for repelling or excluding birds is to stretch wires, monofilament lines, or nylon strings across sites needing protection. Wires or lines spaced at various intervals and in various configurations have successfully repelled birds such as ring-billed (Larus delawarensis) and/or herring (L. argentatus) gulls, and brant (Branta bernicla bernicla) from reservoirs, sanitary landfills, fish hatcheries, nesting areas, public places, or farm fields. Black thread has been suggested for repelling small birds such as sparrows (unspecified) from garden seedlings and bullfinches (unspecified) from fruit trees. Recent observations in New Mexico indicated that monofilament lines spaced at 30-cm (1-ft) intervals repelled house sparrows (Passer domesticus) and other birds from various feeding sites and barn swallows (Hirundo rustica) from nesting sites. Experiments in Nebraska have tested size (1.8-, 5.4-, and 9-kg test), color (clear and fluorescent golden), orientation (north-south, east-west, horizontal, vertical) and/or spacing (30 and 60 cm) of monofilament lines in a grape vineyard and at feeding stations. Results of food consumption and bird count data indicate that all treatments repelled house sparrows. Although the reasons lines repel certain birds is not fully understood, it appears that they have probable applications for excluding or repelling certain terrestrial as well as aquatic species.

RESPONSES OF CAPTIVE COYOTES TO CHEMICAL ATTRACTANTS

Robert L. Phillips et al. — Thu, 08 Feb 2007 11:34:52 PST

Seasonal responses of captive coyotes (Canis latrans) to 9 chemical attractants (W-U lure, TMAD, SFE, FAS, CFA, artificial smoked fish flavor, artificial beef liver flavor, yeast autolysate and decanoic acid) were evaluated. Twenty-six additional attractants were tested only during the summer. W-U lure and FAS produced the greatest total response times from coyotes during all seasons of the year. FAS and smoked fish flavor evoked the most lick-chew-bite and pulling behaviors during the summer and have potential for improving the performance of M-44 devices in warm weather.

AN EVALUATION OF BREAKAWAY SNARES FOR USE IN COYOTE CONTROL

Robert L. Phillips et al. — Thu, 08 Feb 2007 11:32:51 PST

Seven types of breakaway snares were evaluated for breaking strength and variability using a universal testing machine. Maximum tension before breakage for individual snares ranged from 142 to 486 pounds. Sheet metal locks which ripped out, and S-hooks which straightened, provided the least variable results. Coyotes (Canis latrans), mule deer (Odocoileus hemionus), domestic calves and lambs were tested to determine the tension loads they applied to snares. Differences in tension loads among coyotes and nontarget species should allow for the development of snares that will consistently hold coyotes and release most larger nontarget animals.

WILD HOG MANAGEMENT PROGRAM AT GREAT SMOKY MOUNTAINS NATIONAL PARK

John D. Peine et al. — Thu, 08 Feb 2007 11:30:58 PST

Over the last 30 years the wild hog population control program at Great Smoky Mountains National Park has experienced steady growth. The evolution has been relatively slow, and it was not until the latter part of the 1980s that sufficient funds were available to make a serious attempt at control measures. Over the years, the research program has focused on the biology of the wild hog; its reproductive rate; feeding and movement patterns; and its impact on the fauna, flora, and soils of the park. In addition, a major project was conducted to evaluate attractants and baits to increase the trapping success rate in the park. Finally, a population model has been developed to guide management as to the resources necessary to control the population at a satisfactory level. Based on lessons learned, the overall program is reviewed and recommendations are made for a more efficient and effective control program for the 1990s.

REGISTRATION STATUS OF VERTEBRATE PESTICIDES WITH EMPHASIS ON 1080 AND STRYCHNINE

Steve D. Palmateer — Thu, 08 Feb 2007 11:30:57 PST

A review of currently registered vertebrate pesticides is reported with by far the major weight given to strychnine and 1080. The author searched the Agency's label files and has listed most of those pesticides that have claims against at least one vertebrate animal.

RED-WINGED BLACKBIRD AND STARLING FEEDING RESPONSES ON CORN EARWORM-INFESTED CORN

Flavian H. Okurut-Akol et al. — Thu, 08 Feb 2007 11:29:01 PST

We examined the feeding behavior of red-winged blackbirds (Agelaius phoeniceus) and European starlings (Sturnus vulgaris) on ears of corn (Zea mavs) artificially infested with corn earworms (Helicoverpa zea). In 30-minute aviary tests, redwings and starlings directed 39 to 79% more feeding responses to ears of corn with worms than to ears without worms but they damaged the same proportion of ears with and without worms. In 3-hour aviary tests and a field evaluation, birds damaged more ears with worms than without worms. In spite of more feeding responses directed to ears with worms, the overall damage (number of kernels eaten by birds) was similar in both groups of ears in aviary tests. Our findings indicate that earworms can influence feeding behavior by redwings and starlings on ears of corn. The results generally support the hypothesis that by reducing insect populations in cornfields, one can make the fields less attractive to birds. Also, because redwings and starlings actively sought earworms in corn ears, these abundant birds have the potential for reducing populations of these insect pests in cornfields.

VERTEBRATE PESTS OF BEEKEEPING

John M. O'Brien et al. — Thu, 08 Feb 2007 11:26:00 PST

Information concerning vertebrate pests of beekeeping was gathered from state and provincial apiary inspectors through a questionnaire. Forty-eight states and 9 provinces responded. Additional pest information has been assembled from published articles. Bears represent the major vertebrate pest based on severity of damage to colonies. Total estimated losses reported amounted to $623,000 annually. Loss estimates for the various pest species are probably grossly underestimated because many states with problems could not or did not provide loss estimates. Skunks and house mice represent the next most important species from a damage point of view, with annual damage averaging $423,050 and $100,450, respectively. Skunk and house mouse damage, although less severe than that of bears, is far more frequent and widespread. The principal method of damage prevention is the use of electric fencing for bears while trapping is the most used method for control of skunks. Exclusion is considered the best means of resolving house mouse problems. These and a variety of minor vertebrate pests are discussed along with methods or techniques used for their prevention and/or control.

BIRD PROBLEMS IN NEW ZEALAND–METHODS OF CONTROL

Peter C. Nelson — Thu, 08 Feb 2007 11:24:15 PST

New Zealand horticulturists are experiencing increasing damage to a variety of crops from a number of introduced bird species. With the advent of the increasing problem there is a need for carefully planned control operations most of which, by necessity, will be carried out by the growers themselves. This means that a variety of baits and toxins is currently being evaluated for control purposes. Growers are being trained in the use of those toxins as well as how to get more effective use from a range of bird-scare devices. Control agencies continue to carry out control of certain bird species and monitor bird damage where possible.