Environmental Engineering Commons^™

Analysis Of Vertebrate Pest Research, Jim Hone

Vertebrate Pest Conference Proceedings: 17th (1996)

Research on vertebrate pest control is mostly empirical, focusing on control of species X in location Y using method Z. Such an approach is needed. The science of vertebrate pest research is developing some generalizations across species, locations, and methods. This paper further explores such generalizations by discussing six questions asked by Hone (1994), the answers to which are relevant to vertebrate pest research world-wide. Several case studies are examined, with emphasis on control of damage by small mammals and predation control. Suggestions are made for future research.

Operational Control Of The Brown Tree Snake On Guam, Thomas C. Hall

Vertebrate Pest Conference Proceedings: 17th (1996)

An operational control program for brown tree snakes (Boiga irregularis) on Guam began in April 1993. The program focused on minimizing the dispersal of brown tree snakes to other Pacific islands and the U.S. mainland. During the first year of operation, more than 3,000 snakes were caught within a kilometer of high risk port facilities using traps, detector dogs, and spotlighting. Additionally, habitat modifications and prey-base removal were used to reduce the attractiveness of these facilities to brown tree snakes. Public awareness was also an important part of the program such as the education of cargo packers, shippers, …

Rodents And Cover Crops—A Review, Gregory A. Giusti, Desley A. Whisson, W. Paul Gorenzel

Vertebrate Pest Conference Proceedings: 17th (1996)

Inter-row plantings of herbaceous cover crops has become a widely accepted practice by orchard and vineyard managers. Cover crops, used as part of a production management system, are not considered a cash crop and are therefore selected by individual growers for various reasons. Little is written regarding the relationship of cover crop management and the impact on rodent populations. This paper reviews the recent literature and examines how cover crop species and cultivar selection along with management procedures may be influential in limiting rodent populations and their damage to cropping systems.

A Profile Of Depredating Mountain Lions, Steven D. Fairaizl, San Juan Stiver

Vertebrate Pest Conference Proceedings: 17th (1996)

Information regarding the demographics and physical condition of mountain lions (Felis concolof) killed during damage control efforts in Nevada was gathered and compared to sport harvested mountain lions. The average age of depredating male lions was 4.92 years of age compared to 4.95 years for sport harvested males. Depredating female lions were older than sport harvested females averaging 5.09 years compared to 4.44 years. Older age class mountain lions of both sexes were more likely to commit depredations than expected. Male lions were involved in depredations 45 % more often than females. Domestic sheep comprise more than 90% …

The Persistence And Secondary Poisoning Risks Of Sodium Monofluoroacetate (1080), Brodifacoum, And Cholecalciferol In Possums, C. T. Eason, G. R. Wright, L. Meikle, P. Elder

Vertebrate Pest Conference Proceedings: 17th (1996)

To determine the risk of secondary poisoning for animals preying on sub-lethally poisoned brushtail possums, captive possums were treated with near-lethal doses of sodium monofluoroacetate (1080) or brodifacoum, and toxicant concentrations in blood and tissue were monitored over time. Sodium monofluoroacetate was rapidly eliminated from the blood (within three days). Brodifacoum was retained in the liver and, to a lesser extent, the muscle of possums for eight months after dosing. To determine the potential risk for animals scavenging on the carcasses of possums poisoned with cholecalciferol, cats were fed poisoned carcasses for six days. No changes in behavior, appetite, or …

The Texas Oral Rabies Vaccination Project And The Experimental Use Of Raboral V-Rg Rabies Vaccine In The South Texas Coyote Rabies Epizootic, M. Gayne Fearneyhough

Vertebrate Pest Conference Proceedings: 17th (1996)

Beginning in October 1988, Texas experienced the onset of an expanding epizootic of canine rabies in South Texas. That epizootic now involves 21 counties, with 678 laboratory confirmed cases as of February 1996. Approximately 50% of those cases have occurred in coyotes and most of the remainder in domestic dogs. Seventy-six "spill over" cases have been reported in seven other species, both wild and domestic. Since 1991, over 2,000 people in South Texas have received post exposure rabies treatment due to potential exposure to a rabid animal and two human deaths have been attributed to this virus strain. The Texas …

Use Of The Modified Australian Crow Trap For The Control Of Depredating Birds In Sonoma County, Pierre Gadd Jr

Vertebrate Pest Conference Proceedings: 17th (1996)

The Modified Australian Crow (MAC) trap to control depredating birds can be a very humane, target species specific and effective bird control tool. Pertinent topics will include legal status, timing, and care of trapped birds. The following are also discussed: species identification, trap construction, and placement and humane euthanasia methods.

Leg Injuries To Coyotes Captured In Standard And Modified Soft Catch® Traps, Kenneth S. Gruver, Robert L. Phillips, Elizabeth S. Williams

Vertebrate Pest Conference Proceedings: 17th (1996)

Leg injuries of coyotes (Canis latrans) captured in standard No. 3 Soft Catch traps were compared with those captured in the same trap type modified with two additional coil springs. One hundred thirteen coyotes were trapped in southern California in conjunction with livestock predator control operations, 53 in standard traps, and 60 in modified traps. Observed injuries were similar in both trap types. The most frequent injuries were edematous hemorrhages and small cutaneous lacerations. Injuries, such as joint luxations and bone fractures, were noted more frequently for coyotes trapped in standard Soft Catch traps.

The Use Of Tip Traps To Control Rabbit Damage In Scotland, Robert M. E. Fuchs, W. Kenneth Maclean, Caroline A. Mackintosh, Iain M. Allan

Vertebrate Pest Conference Proceedings: 17th (1996)

The factors affecting efficient use of tip traps to control rabbit populations were investigated in a series of field experiments. It was found that continual trapping at the same location was much less effective than periodic trapping. Night-time trapping operations produced larger catches of rabbits than day-time trapping. Traps were equally effective whether sited on existing runs through rabbit proof fences or on previously unbreached sections of fence. The sex ratio of rabbits caught was examined at four different locations and, in each instance, more females were caught than males. The installation of a network of tip traps and associated …

Economic Effectiveness, Efficiency, And Selectivity Of Fox Squirrel Trapping In Pecan Groves, J. Grant Huggins

Vertebrate Pest Conference Proceedings: 17th (1996)

Trapping is the most common damage management practice employed by pecan growers suffering fox squirrel (Sciurus niger) depredation. The author evaluated the economic effectiveness of foot-hold trapping fox squirrels in native pecan groves from 1988 to 1991. Trapping significantly reduced squirrel damage the first and second year of treatment in all three study areas relative to the initial untreated year. This reduction was valued at $38.63 to $279.51/ha. In 1990 the author tested the relative efficiency and selectivity of five trap types. Number 110 body traps performed with the best combination of efficiency, selectivity, and cost of the …

Perceptions Of Wildlife Damage By Conservation Reserve Program Contract Holders In Riley County, Kansas, John P. Hughes, Philip S. Gipson

Vertebrate Pest Conference Proceedings: 17th (1996)

Twenty-five Conservation Reserve Program (CRP) contract holders in Riley County, Kansas were surveyed by telephone to assess their perceptions of wildlife damage relative to CRP plantings. Sixty-four percent experienced wildlife damage on their farm or ranch. Respondents felt that five species causing damage on their farm or ranch had become more common due to enrollment of lands in the CRP. White-tailed deer (Odocoileus virginianus) accounted for 64.3% of these observations, followed by wild turkey (Meleagris gallopavo), eastern cottontail (Sylvilagus floridanus), striped skunk (Mephitis mephitis), and Virginia opossum (Didelphis virginiana), which accounted for …

The Potential Impact Of Introduced Commensal Rodents On Island Flora, Gillian Key, Renata Platenberg, Andrew Easby, Kathleen Mais

Vertebrate Pest Conference Proceedings: 17th (1996)

The impact of introduced commensal rodents on island flora has been relatively little studied compared with their impact on the fauna. The effects on vegetation composition, regeneration, and decomposition are largely unknown, but potentially great. Preliminary studies were carried out in the Galapagos Islands between 1993 and 1994 on the diet of introduced rats, Rattus spp. and feral house mice, Mus musculus, seed recovery rates and subsequent germination rates of seeds. R. rattus diet was primarily vegetation and 48% of rats had seeds in their stomachs. Significant differences were found between body size and overall contribution of both …

The Status Of Nuisance Wildlife Damage Control In The States, Kristen P. La Vine, Mark J. Reeff, Jodi A. Dlcamillo, Gary S. Kama

Vertebrate Pest Conference Proceedings: 17th (1996)

State fish and wildlife agencies and nuisance wildlife control operators must work together whether or not they actively choose to. In this paper, their relationship is likened to a marriage between two (not so likely) partners. In an attempt to assess the status of this relationship the International Association of Fish and Wildlife Agencies, The Wildlife Society's Wildlife Damage Management Working Group, and the National Animal Damage Control Association developed a survey that addressed the level of state agencies' oversight of nuisance wildlife control operators (NWCOs). Responses were received from 47 states, 1 territory, and 17 ADC state offices. This …

The Distribution And Significance Of Anticoagulant-Resistant Norway Rats (Rattus Norvegicus) In England And Wales, 1988-95, Alan D. Macnicoll, Gerard M. Kerbms, Nicola J. Dennis, J. Erica Gill

Vertebrate Pest Conference Proceedings: 17th (1996)

Between 1988 and 1995 populations of rats on agricultural premises were sampled to investigate the distribution of anticoagulant-resistant rats in England and Wales. In total, approximately 1,670 rats from 115 locations were tested for resistance to warfarin. Rats that were warfarin-resistant were subsequently tested for resistance to difenacoum, and since 1991 for resistance to bromadiolone. In some cases rats were also tested for resistance to brodifacoum, and in 1995 for resistance to flocoumafen. The results of these tests showed that there was a high prevalence of resistance to the first-generation anticoagulant, warfarin, in several regions of England and Wales. Rats …

Mole Control-A Historical Perspective, Rex E. Marsh

Vertebrate Pest Conference Proceedings: 17th (1996)

Various methods and approaches, including chemical and physical repellents, flooding, burrow fumigants, poison baits, vibrating devices and exclusion, have been explored for reducing mole problems. In addition to these, habitat management through reducing the moles food supply has received considerable attention, but environmental concerns and the lack of consistent results have tempered this approach. Over the years, trapping remains the best and most useful method of mole control. The pros and cons of some of the methods are discussed, along with some historical perspectives. The emphasis is placed on the Broad-footed mole, Scapanus latimanus, of California.

Federal And State Fish And Wildlife Regulations And Other Pertinent California Laws, Lee R. Martin

Vertebrate Pest Conference Proceedings: 17th (1996)

Working knowledge of Federal and State Fish and Wildlife regulations and other laws are critical for today's commercial applicator in the vertebrate pest control business. The ever-changing focus on environmental protection, endangered species considerations, occupational health and safety, and animal rights have put vertebrate pest control operators in the precarious position of correctly interpreting the steady stream of laws and regulations passed by government. The consequences of failing to stay abreast of these changing regulations and correctly interpreting them can lead to very costly fines and possible imprisonment. Maintaining close contact with the many agencies that regulate the pest control …

Results Of A Non-Lethal Survey And Report Provided To The New Mexico Legislature, J. Alan May

Vertebrate Pest Conference Proceedings: 17th (1996)

Social and political pressures affect decision making regarding wildlife damage management issues tremendously. In fact, these areas are included in the Animal Damage Control decision model outlined in the programmatic Environmental Impact Statement. Growing concern regarding pain and suffering of animals trapped by ADC Specialists prompted two actions by the 41st Legislature of the State of New Mexico in 1994. The legislature directed New Mexico ADC not to spend over three-quarters of its $304,000 appropriation on lethal methods. The legislature also passed a memorial bill requesting the New Mexico Department of Game and Fish, in cooperation with the U.S. Fish …

Developing Wildlife Management Into A Successful Business, Peter C. Nelson

Vertebrate Pest Conference Proceedings: 17th (1996)

Wildlife management has been developed into a successful business. The company was set up after the principal shareholder was made redundant after over 30 years in the wildlife management field. The company has been successful, as it diversified into a consultancy and supply company, and targeted a wide range of animal species and equipment.

Mongolian Rangelands: Rodent Problems And Approaches To Alleviate Damage, Dale L. Nolte

Vertebrate Pest Conference Proceedings: 17th (1996)

Rodents are a major constraint to forage production for livestock in Mongolia. A technical program to identify the magnitude of the problem and strengthen the research capabilities of Mongolian rodent specialists was initiated in 1994. The Brandt's vole is the most widespread and the most detrimental rodent to the steppes of Mongolia. Limited resources inhibit activities by the Mongolian Plant Protection Service to reduce rodent populations. Alternative means to monitor vole activity were developed. Laboratory and field trials showed that voles were susceptible to zinc phosphide treatment and indicated how bait acceptance could be improved.

Conference Participants

Vertebrate Pest Conference Proceedings: 17th (1996)

The number of registered attendees was 340. The participants came from 31 states, the District of Columbia, and from 9 other countries. The wide representation from the United States and countries throughout the world contributed to the success of the Conference by providing a highly knowledgeable and diversified group for the exchange of research progress, new ideas, and information on a wide range of vertebrate pest topics.

Preliminary Study Of The Genetics Of Resistance In The House Mouse, Colin V. Prescott

Vertebrate Pest Conference Proceedings: 17th (1996)

A wild house mouse (Mus domesticus) population originally trapped near Reading, Berkshire, United Kingdom, and maintained as a colony in the laboratory, was subjected to the discriminating feeding period of the warfarin resistance test, as used by Wallace and MacSwiney (1976) and derived from the work of Rowe and Redfern (1964). Eighty percent of this heterogeneous population survived the resistance test. A similar proportion of the population was found to survive the normally lethal dose of bromadiolone administered by oral gavage. The majority of this population of mice were classified as "warfarin-resistant" and "bromadiolone-resistant." The dose of l0 …

Palatability Of Rodenticide Baits In Relation To Their Effectiveness Against Farm Populations Of The Norway Rat, Roger J. Quy, David P. Cowan, Colin Morgan, Tom Swevney

Vertebrate Pest Conference Proceedings: 17th (1996)

The palatability of 12 rodenticide baits, formulated to vary from poorly accepted to well accepted, was measured in laboratory choice tests against Wistar and wild-caught Norway rats. The baits, derived from six bait bases and two active ingredients, difenacoum and bromadiolone, were simultaneously tested in the field against 24 farm infestations (2/formulation) in order to investigate the relationship between palatability and efficacy. Bait acceptance in laboratory tests, with EPA meal as the challenge diet, varied from 7.0 to 50.6% for Wistar rats and 3.7 to 85.1 % for wild rats. Changing the challenge diet to a ground-up laboratory animal food …

The Evolution Of Aphis Two Gas Cartridges, Craig A. Ramey, Edward W. Schafer Jr

Vertebrate Pest Conference Proceedings: 17th (1996)

The U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) has two federal (Section 3) vertebrate pesticide registrations with the U.S. Environmental Protection Agency (EPA) for gas cartridges to control damage to American agricultural resources and reduce threats to public health and safety. The gas cartridges are pyro-fumigant devices that produce primarily carbon monoxide when ignited. In sealed burrows or dens, carbon monoxide is highly toxic when inhaled, leading to tissue hypoxia. Carbon monoxide is recommended by the American Veterinary Medicine Association's panel for euthanatizing animals because it quickly induces unconsciousness without pain and with minimal discernible discomfort. …

Agelaius Blackbirds And Rice In Uruguay And The Southeastern United States, Ethel N. Rodriguez, Michael L. Avery

Vertebrate Pest Conference Proceedings: 17th (1996)

Throughout the world, wherever rice is grown, birds that damage the crop are attracted. The situations are particularly interesting in Uruguay and the southeastern United States where different species of blackbird have adapted to rice cultivation. In the two countries, rice production practices differ in several respects such as seeding rate, seedbed preparation, and insect control practices. Furthermore, although they are congeneric, the major rice pest species differ in important ways. For example, in Uruguay, Agelaius ruficapillus usually nests in the rice field, whereas A. phoeniceus, in the U.S., does so only rarely. Agronomic and ornithological aspects of these …

Nest Material As A Delivery Method For Avicides: Preliminary Tests With African Weaver Finches, Stephen A. Shumake, Peter J. Savarie

Vertebrate Pest Conference Proceedings: 17th (1996)

To evaluate the potential of using nesting material as a medium for avicide delivery, five organophosphates (Dasanit^®, Volaton^®, fenthion, parathion, and Cyanophos^®) were tested on small groups of paired male-female quelea (n = 4 to 9). Toxicants were presented to each pair of birds on five 13-cm strands of cotton string after a preliminary screening for male nest weaving behavior. Tested concentrations ranged from 100% technical grade to 0.003 % compound diluted with acetone. Dasanit^® was found to be the most effective candidate with some lethal effects noted at 0.012%. An optimal concentration …

Zinc Phosphide Residues In Voles: Scenarios Showing Low Risks To Domestic Cats And Dogs, Ray T. Sterner

Vertebrate Pest Conference Proceedings: 17th (1996)

Zinc phosphide (Zn₃P₂, CAS #1314-84-7) is an acute rodenticide having numerous agricultural applications. This paper estimates the risk of mortality posed to domestic cats (Felis domesticus) and dogs (Canis familiaris) from ingestion of voles (Microtus spp.) that succumb to 2.0% Zn₃P₂ baits. Following a brief review of direct/indirect studies and incident reports relevant to nontarget-Zn₃P₂ effects and vole control, four scenarios of volecarcass ingestions needed for light and heavy cat and dog predators/scavengers to receive approximate lethal doses (ALDs = 40 mg/kg) of undigested rodenticide …

Population Densities And Disease Surveys Of Wild Pigs In The Coast Ranges Of Central And Northern California, Rick A. Sweitzer, Ian A. Gardner, Ben J. Gonzales, Dirk Van Vuren, Walter M. Boyce

Vertebrate Pest Conference Proceedings: 17th (1996)

In 1994 and 1995, 233 different wild pigs were captured during population research at seven research sites focused primarily in the coastal regions of central and northern California. Mark-resight data and information on wild pig movements were used to assess wild pig population densities at those sites. Population densities ranged from 1.01 wild pigs/km² in Mendocino County in 1994 to 3.32 wild pigs/km² in Santa Clara County in 1995. Comparisons of population densities between years at three research sites suggested that wild pig populations increased in 1995 in response to favorable forage conditions after the wet fall and …

Opening Remarks - Seventeenth Vertebrate Pest Conference, Robert M. Timm

Vertebrate Pest Conference Proceedings: 17th (1996)

It is my honor and my pleasure to greet you this morning, and to welcome you on behalf of the entire Vertebrate Pest Council.

You have come from throughout California, from across the United States, and from many corners of the world to gather here for the purpose of sharing information, expertise, and wisdom in dealing with vertebrate pest problems. Our common purpose is to find yet better methods for preventing and resolving situations in which wildlife comes into conflict with humans. The Conference's mission remains one of education. We learn from each other, and we strive to find better …

Effects Of Stage Of Nut Development And Simulated Rat Damage On Macadamia Yields, Mark E. Tobin, Ann E. Koehler, Robert T. Sugfflara, Richard M. Engeman

Vertebrate Pest Conference Proceedings: 17th (1996)

Black rats (Rattus rattus) cause extensive damage in Hawaiian macadamia (Macadamia integrifolia) orchards. In a previous study, extensive and persistent snap trapping significantly reduced rat populations and depredations on developing macadamia nuts, but had little effect on subsequent yields of mature nuts. This suggested that macadamia trees may compensate for rat damage, and that commonly used indices based on rodent activity and proportion of nuts damaged may overestimate the impact of rodent depredations and exaggerate the effectiveness of control measures. To clarify the effects of rat feeding on developing macadamia nuts, two levels of damage at …

Investigations And Management Of Epizootic Plague At Ice House Reservoir, Eldorado National Forest, California, 1994 And 1995, Kenneth R. Townzen, Malcolm A. Thompson, Charles R. Smith

Vertebrate Pest Conference Proceedings: 17th (1996)

The occurrence of plague (Yersinia pestic) at Ice House Reservoir in 1994 and 1995 was characteristic of widespread epizootics in high use recreational areas of California. Staff of the Vector-Borne Disease Section investigated these epizootics and found dense populations of plague susceptible California ground squirrels (Spermophilus beecheyi) with high numbers of fleas, primarily Diamanus montanus, the most important plague vector. This combination indicated a high risk of plague exposure to campground users. A non-fatal human case of plague, contracted at Mountain Camp II, was reported after the initial epizootic investigation. The patient's exposure occurred prior …