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United States Department of Agriculture Wildlife Services: Staff Publications

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Is It A Pocket Gopher Or Mole?, Wendy M. Arjo Jul 2003

Is It A Pocket Gopher Or Mole?, Wendy M. Arjo

United States Department of Agriculture Wildlife Services: Staff Publications

Depending on where you are, the term “gopher” is applied to a variety of mammal species including ground squirrels, prairie dogs and moles. The true pocket gopher is actually very distinguishable once you recognize their appearance and sign, or indicators of the animal. Pocket gophers are burrowing rodents named for their external fur-lined cheek pouches. Unlike mole mounds, which have been characterized as miniature volcanoes, gopher mounds are fan-shaped in appearance. Pocket gophers are distributed throughout the Pacific Northwest, but occur more frequently in the drier climates of eastern Washington and Oregon.

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The Role Of Toxicants In Forest Management, Wendy M. Arjo Jul 2003

The Role Of Toxicants In Forest Management, Wendy M. Arjo

United States Department of Agriculture Wildlife Services: Staff Publications

Although the emphasis of the Olympia Field Station is on the development of non-lethal methods to control pest species, sometimes lethal methods are necessary. Toxicants can be an effective means of quickly reducing high populations of some problem animals or maintaining acceptable population densities. Depending on their mode of action, toxicants are classified into three categories: fumigants, acute toxicants and chronic toxicants.

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Developing Approaches To Reduce Wildlife Damage To Forest Resources, Dale L. Nolte Jul 2003

Developing Approaches To Reduce Wildlife Damage To Forest Resources, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife impacts on forest resources can be extensive. Although damage is generally considered in terms of reduced productivity or delayed harvest cycles, attempts to replace trees after a harvest or a fire can fail because of foraging wildlife. Wildlife, particularly mammalian herbivores, can impede attempts to establish native plants to increase forest diversity, improve riparian areas, re-vegetate disturbed sites, restore endangered or threatened plants, or to create or improve habitat for wildlife. Foraging wildlife can be extremely detrimental if animals browse on plants before seedlings are well established, or if foraging is continuous or intense. Native plant projects are often …

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Developing Strategies To Alleviate Wildlife Damage To Forest Resources, Dale L. Nolte Jul 2003

Developing Strategies To Alleviate Wildlife Damage To Forest Resources, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

Does the presence of wildlife always pose a problem when reforesting a site? Not necessarily. However, the potential impacts of wildlife need to be considered. The intensity or severity of impacts caused by wildlife will reflect the species and density of animals present, along with existing habitat conditions. Whether these impacts create a problem depends on the objectives of the producer and the resources available to achieve the original goal. Wildlife will not be a problem for projects with unlimited resources and time. The repeated plant and replant methods will ultimately lead to some form of success. However, wildlife can …

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Mountain Beaver: The Little Rodent With A Large Appetite, Wendy M. Arjo Jul 2003

Mountain Beaver: The Little Rodent With A Large Appetite, Wendy M. Arjo

United States Department of Agriculture Wildlife Services: Staff Publications

While walking through open forest areas you might have found yourself falling into large holes that dot the landscape. After extracting your foot from the hole you may have noticed other holes nearby, some with clipped sword fern or forbs neatly arrayed around the hole. These symmetrical burrows are home to the mountain beaver. The mountain beaver, considered the most primitive living rodent species, descended from a now extinct family of rodents over 30 million years ago. Seven subspecies of mountain beaver are recognized with one subspecies in coastal California currently listed as an endangered species. This semi-fossorial rodent, endemic …

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Fencing Out Big Game Species, Dale L. Nolte Jul 2003

Fencing Out Big Game Species, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

Fencing is the most effective approach to deter big-game movements. However, cost to install and maintain effective fences can be prohibitive. Further, fences across rough terrain can be impractical. Although simple designs can effectively deter deer and elk from some sites, more complex designs are necessary if the protected resource is highly desirable or if normal transitory patterns, such as migratory routes or paths to water, are disrupted. The task becomes more daunting if your desire is to construct an impregnable fence.

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Predators On Red-Winged Blackbird Nests In Eastern North Dakota, Richard S. Sawin, Mark W. Lutman, George M. Linz, William J. Bleier Jul 2003

Predators On Red-Winged Blackbird Nests In Eastern North Dakota, Richard S. Sawin, Mark W. Lutman, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Predation has consistently been identified as the most common cause of nest failure for Red-winged Blackbirds (Agelaius phoeniceus). During May and June, 2000 and 2001, we used infrared-triggered camera systems to identify potential nest predators on artificially relocated Red-winged Blackbird nests in eastern North Dakota. For some of the species observed, these observations represent the first documentation of predation on Red-winged Blackbird nests in the northern Great Plains.

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West Nile Virus And Wildlife Health, Peter P. Marra, Sean M. Griffing, Robert G. Mclean Jul 2003

West Nile Virus And Wildlife Health, Peter P. Marra, Sean M. Griffing, Robert G. Mclean

United States Department of Agriculture Wildlife Services: Staff Publications

The West Nile Virus and Wildlife Health Workshop, hosted by the Smithsonian Institution, National Audubon Society, U.S. Geological Survey, and U.S. Department of Agriculture, was held February 5–7, 2003, at the Smithsonian Environmental Research Center in Edgewater, Maryland. The event was attended by more than 100 scientists, who heard 29 speakers and participated in strategy discussions during the 2-day meeting. The main focus of the conference was the present and future impact of West Nile virus on wildlife populations. Talks and discussions emphasized how basic research, public health, and land management can contribute to our understanding of the disease’s impact …

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Population Monitoring In Support Of A Rabies Vaccination Program For Skunks In Arizona, Richard M. Engeman, Kevin L. Christensen, Michael J. Pipas, David L. Bergman Jul 2003

Population Monitoring In Support Of A Rabies Vaccination Program For Skunks In Arizona, Richard M. Engeman, Kevin L. Christensen, Michael J. Pipas, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

Three population monitoring methods were evaluated in support of a trap/vaccinate/release program for controlling a bat variant of rabies virus in skunks (Mephitis mephitis) in Flagstaff, Arizona (USA). Skunks were the primary species targeted for population monitoring during the program, but feral cats were also monitored as they represented an abundant secondary vector species capable of rabies transmission. Skunks were vaccinated and released, except for a subset tested for rabies. All captured cats were placed in the local animal shelter. Spotlight surveys essentially did not detect skunks, and were not able to detect reductions in the cat population. …

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Nwrc: Providing World Leadership In Science-Based Problem Management, J. Russell Mason Jul 2003

Nwrc: Providing World Leadership In Science-Based Problem Management, J. Russell Mason

United States Department of Agriculture Wildlife Services: Staff Publications

he National Wildlife Research Center (NWRC) functions as the research arm of the Wildlife Services (WS) program, an agency of the U.S. Department of Agriculture, Animal and Plant Health Inspection Service. Located on the Foothills campus of Colorado State University, WS-NWRC helps WS manage wildlife conflicts by providing scientific information on damage or threats to human health and safety, and by developing new tools and management techniques. WS-NWRC research activities emphasize economically, environmentally and socially acceptable methods that reduce or stop wildlife damage effectively without risk to humans, wildlife or the natural environment.

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Managing Ungulates To Protect Trees, Dale L. Nolte Jul 2003

Managing Ungulates To Protect Trees, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

ig game species, such as elk and deer, inflict the most widespread form of damage to forest resources. Elk may trample or pull seedlings without well-established root systems out of the ground. Browsing elk often splinter woody stems. During the spring, the stems may be stripped of bark below where they break the stem. Deer damage inflicted on seedlings is similar to elk damage. Woody stems are often splintered and the bark is stripped from twigs. New buds are generally clipped back to the previous year’s growth. Deer do not pull seedlings as frequently as elk and their damage rarely …

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Repellents Are Socially Acceptable Tools, Dale L. Nolte Jul 2003

Repellents Are Socially Acceptable Tools, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

The likelihood of a particular plant being consumed by an animal depends on its palatability, along with the availability and relative desirability of alternative foods. Repellents, therefore, can be applied to plants to render them less attractive than the alternative foods. In theory, animals then select for plants or foraging areas other than those protected with repellents. Repellents are socially acceptable nonlethal tools to reduce wildlife damage. New products are continually entering the market, but their efficacy varies greatly. Unfortunately, availability or even registration of these products does not equate to effectiveness. Some repellents contain aversive agents at concentrations below …

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Bears Prefer Trees In The Spring, Dale L. Nolte Jul 2003

Bears Prefer Trees In The Spring, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

As they emerge from their winter den, bears need an energy source and food is relatively scarce. Concurrently, trees are breaking dormancy and starting to generate carbohydrates. Consequently, bears commonly girdle Douglas-fir trees during the spring to feed on the available carbohydrates. Bears strip bark from a tree with their claws, then feed on the sapwood by scraping it from the heartwood with their teeth. Scattered remnants of bark strewn at the base of a tree and vertical tooth marks are characteristic indicators of bear activity. Most frequently bears forage on the lower bole of trees, girdling the bottom three …

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4,4'-Dinitrocarbanilide (Dnc) Concentrations In Egg Shells As A Predictor Of Nicarbazin Consumption And Dnc Dose In Goose Eggs, Randal S. Stahl, Kurt C. Vercauteren, Dennis Kohler, John J. Johnston Jun 2003

4,4'-Dinitrocarbanilide (Dnc) Concentrations In Egg Shells As A Predictor Of Nicarbazin Consumption And Dnc Dose In Goose Eggs, Randal S. Stahl, Kurt C. Vercauteren, Dennis Kohler, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

Nicarbazin is being investigated as an infertility agent for the control of non-migratory Canada geese (Branta canadensis L) populations. Nicarbazin is presently registered for use as a coccidiostat for poultry. Geese fed sufficient quantities of nicarbazin will lay non-viable eggs. We established nicarbazin consumption by measuring the concentration of a component of the formulation, 4,4’-dinitrocarbanilide (DNC) in the egg contents (yolk, albumin) in non-viable eggs. To estimate the nicarbazin consumption of birds that laid viable eggs (eggs that hatched or contained an embryo), a high-performance liquid chromatography method was developed to measure the concentration of DNC in egg …

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Determination Of 4,4'-Dintrocarbanilide (Dnc), A Component Of Nicarbazin, In Canada Goose (Branta Canadensis) Eggshells Using High-Performance Liquid Chromatography, Randal S. Stahl, Kurt C. Vercauteren, Teresa L. Buettgenbach, John J. Johnston Jun 2003

Determination Of 4,4'-Dintrocarbanilide (Dnc), A Component Of Nicarbazin, In Canada Goose (Branta Canadensis) Eggshells Using High-Performance Liquid Chromatography, Randal S. Stahl, Kurt C. Vercauteren, Teresa L. Buettgenbach, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

A method was developed using high-performance liquid chromatography to assay 4,4'-dinitrocarbanilide (DNC), the active ingredient in Nicarbazin, in eggshells collected from Canada geese fed a formulated feed fortified with Nicarbazin at doses of 0, 125, 250, and 500 μg/g. The method was developed using chicken eggshells fortified with DNC. The method was used to quantify DNC in both the shell-associated membranes and the calcified shell extracellular matrix. These values were compared to those obtained for a composite sample consisting of both the membranes and the calcified shell extracellular matrix. The validated method was used to quantify DNC in eggshells from …

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Cool Temperatures Elicit Reproduction In A Biologically Invasive Predator, The Brown Treesnake (Boiga Irregularis), Tom Mathies, Lowell A. Miller May 2003

Cool Temperatures Elicit Reproduction In A Biologically Invasive Predator, The Brown Treesnake (Boiga Irregularis), Tom Mathies, Lowell A. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Two different temperature regimes for eliciting reproduction in male and females of the Guam form of the brown treesnake were investigated. Males and females maintained at 24°C followed by a 60-day cool period at 19°C exhibited substantial reproductive activity, and the females that produced clutches did so during a brief period after return to 24°C. In contrast, individuals maintained at 28°C followed by an identical 19°C cooling period exhibited relatively little reproductive activity, and although some females became vitellogenic, none produced eggs. Reproductive activity was virtually absent in all individuals in both groups 7 months after the end of the …

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Rodent Hunt, Dr. Ray Sterner May 2003

Rodent Hunt, Dr. Ray Sterner

United States Department of Agriculture Wildlife Services: Staff Publications

The Dryland Project is a multi-year research effort to identify no-tillage or reduced tillage, non-irrigated crop types and practices that will improve yields and soil characteristics in eastern Colorado. Left uncultivated, this is shortgrass prairie made up of blue grama, western wheatgrass, buffalo grass, prickly pear cactus, yucca shrub, plus other plant varieties, and laced with riparian stream flows. When cultivated, winter wheat has worked well here, as long as it is left idle biannually (alternated as fallow) to restore sufficient moisture for the next cycle. Alternative dryland crops and rotation schemes are being studied as a way to reduce …

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Amount And Economic Valuation Of Feral Hog Damage To A Unique Basin Marsh Wetland In Florida, Richard M. Engeman, Henry T. Smith, Robert G. Severson, Mary Ann M. Severson, Stephanie A. Shwiff, Bernice Constantin, Daniel Griffen Apr 2003

Amount And Economic Valuation Of Feral Hog Damage To A Unique Basin Marsh Wetland In Florida, Richard M. Engeman, Henry T. Smith, Robert G. Severson, Mary Ann M. Severson, Stephanie A. Shwiff, Bernice Constantin, Daniel Griffen

United States Department of Agriculture Wildlife Services: Staff Publications

Feral hogs (Sus scrofa) have been introduced into many natural habitats throughout the world, and they have adversely affected the environment in most of those places. Basin marshes are unique, but dwindling ecosystems in Florida that are especially vulnerable to damage by feral hogs. We estimated the amount of hog damage to the last remnant of a basin marsh system in Savannas Preserve State Park (SPSP), and to ecotones within the marsh. We also applied an economic valuation method for the hog damage that was based on the dollar amounts that wetland regulators have allowed permit applicants to …

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Age-Specific Reproduction By Female Laughing Gulls (Larus Atricilla), Richard A. Dolbeer, Glen E. Bernhardt Apr 2003

Age-Specific Reproduction By Female Laughing Gulls (Larus Atricilla), Richard A. Dolbeer, Glen E. Bernhardt

United States Department of Agriculture Wildlife Services: Staff Publications

The age at which female gulls first reproduce is poorly documented. We examined plumage and reproductive organs of Laughing Gulls (Larus atricilla) collected from May–August 2000–2001 at John F. Kennedy International Airport, New York, to determine age-specific reproductive effort. Each gull was classified as one year old (hatched in previous year), two years old, or ≥3 years old on the basis of color patterns of the hood and tail feathers and fifth primary flight feather. For females, each ovary was examined to determine if postovulatory follicles were present. In 2000 and 2001, the first gulls with postovulatory follicles were recorded …

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Impacts Of Small Mammals And Birds On Low-Tillage, Dryland Crops, Ray T. Sterner, Brett E. Petersen, Stanley E. Gaddis, Kenneth L. Tope, David J. Poss Apr 2003

Impacts Of Small Mammals And Birds On Low-Tillage, Dryland Crops, Ray T. Sterner, Brett E. Petersen, Stanley E. Gaddis, Kenneth L. Tope, David J. Poss

United States Department of Agriculture Wildlife Services: Staff Publications

During 2000–2001, small mammals, birds, and potential corn/soybean damage were studied at a low-tillage, non-irrigated agricultural research site in the Colorado Piedmont. A small mammal surveyinvolved four trapping sessions and 18, 12-live-trap grids each. Within years, two grids each were placed at random, fixed locations in experimental corn, fallow, millet, pea, soybean, sunflower, and wheat plots at the site; two off-plot grids each were set at random, fixed locations <100m from the north and south edge of these plots. In 2001, periodic bird observations were conducted, and damage to corn and soybean plants was assessed. Capture rates were low during all trap sessions (range 0.1%–3.3%, Χ̅ = 2:2%). Sixty-three small mammals were captured and 39 were recaptured. Captures included deer mouse (Peromyscus maniculatus), northern grasshopper mouse (Onychomys leucogaster), thirteen-lined ground squirrel (Spermophilus tridecemlineatus), and western harvest mouse (Reithrodontomys megalotis). Deer mice accounted for 56 of …

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Serologic Survey For Diseases In Free-Ranging Coyotes (Canis Latrans) From Two Ecologically Distinct Areas Of Utah, Wendy M. Arjo, Eric M. Gese, Cassity Bromley, Adam Kozlowski, Elizabeth S. Williams Apr 2003

Serologic Survey For Diseases In Free-Ranging Coyotes (Canis Latrans) From Two Ecologically Distinct Areas Of Utah, Wendy M. Arjo, Eric M. Gese, Cassity Bromley, Adam Kozlowski, Elizabeth S. Williams

United States Department of Agriculture Wildlife Services: Staff Publications

The influence of habitat and associated prey assemblages on the prevalence of canine diseases in coyotes (Canis latrans) has received scant attention. From December 1997 through December 1999, we captured 67 coyotes in two ecologically distinct areas of Utah (USA): Deseret Land and Livestock Ranch and US Army Dugway Proving Ground. These areas differ in habitat and prey base. We collected blood samples and tested for evidence of various canine diseases. Prevalence of antibodies against canine parvovirus (CPV) was 100% in the Deseret population and 93% in the Dugway population. All juveniles in both populations had been exposed. …

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Prevalence Of Antibodies To Neospora Caninum, Sarcocystis Neurona, And Toxoplasma Gondii In Wild Horses From Central Wyoming, J. P. Dubey, S.M. Mitchell, J.K. Morrow, J.C. Rhyan, L.M. Stewart, D.E. Granstrom, S. Romand, P. Thulliez, W.J. Saville, D.S. Lindsay Mar 2003

Prevalence Of Antibodies To Neospora Caninum, Sarcocystis Neurona, And Toxoplasma Gondii In Wild Horses From Central Wyoming, J. P. Dubey, S.M. Mitchell, J.K. Morrow, J.C. Rhyan, L.M. Stewart, D.E. Granstrom, S. Romand, P. Thulliez, W.J. Saville, D.S. Lindsay

United States Department of Agriculture Wildlife Services: Staff Publications

Sarcocystis neurona, Neospora caninum, N. hughesi, and Toxoplasma gondii are 4 related coccidians considered to be associated with encephalomyelitis in horses. The source of infection for N. hughesi is unknown, whereas opossums, dogs, and cats are the definitive hosts for S. neurona, N. caninum, and T. gondii, respectively. Seroprevalence of these coccidians in 276 wild horses from central Wyoming outside the known range of the opossum (Didelphis virginiana) was determined. Antibodies to T. gondii were found only in 1 of 276 horses tested with the modified agglutination test using 1: 25, 1:50, …

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Common Raven Nests In Eastern Kentucky, John J. Cox, Nathan W. Seward, Jeffrey L. Larkin, David S. Maehr Mar 2003

Common Raven Nests In Eastern Kentucky, John J. Cox, Nathan W. Seward, Jeffrey L. Larkin, David S. Maehr

United States Department of Agriculture Wildlife Services: Staff Publications

Although ravens were once widespread throughout Appalachia they are now considered threatened or endangered in many states of the region. We document a nesting pair of common ravens in an area of southeastern Kentucky nearly 50 km northwest of traditional nesting sites. Further, we suggest several factors that may have influenced the patterns of raven abundance in the state and offer management recommendations to assist their recovery.

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Mitigating Impacts Of Terrestrial Lnvasive Species, Kathleen A. Fagerstone Mar 2003

Mitigating Impacts Of Terrestrial Lnvasive Species, Kathleen A. Fagerstone

United States Department of Agriculture Wildlife Services: Staff Publications

Human beings have introduced other species around the world both accidentally and intentionally. Accidental introductions resulted from escape from captivity (monk parakeets [Myiopsitta monachus] in Florida), stowaways (rats [Ranus spp.] and house mice [Mus musculus] worldwide; brown tree snakes [Boiga irregularis] in Guam), or expansion of species' ranges. Intentional introductions occurred for various reasons including: 1) aesthetics (songbirds into Hawaii, grey squirrel [Sciurus carolinensis] into Europe, and European songbirds imported by British colonists into North America, Australia, and New Zealand); 2) economics (nutria [Myocastor coypus] introduced in the …

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Feasibility Of Non-Lethal Approaches To Protect Riparian Plants From Foraging Beavers In North America, Dale L. Nolte, Mark W. Lutman, David L. Bergman, Wendy M. Arjo, Kelly R. Perry Mar 2003

Feasibility Of Non-Lethal Approaches To Protect Riparian Plants From Foraging Beavers In North America, Dale L. Nolte, Mark W. Lutman, David L. Bergman, Wendy M. Arjo, Kelly R. Perry

United States Department of Agriculture Wildlife Services: Staff Publications

Beavers in North America will occupy almost any wetland area containing available forage. Wetland restoration projects often provide the resources necessary for dispersing beavers to create desirable habitats. Their wide distribution and ability to disperse considerable distances almost assure that beavers will establish themselves in new wetlands. Although beavers are a natural and desirable component of a wetland ecosystem, their foraging behaviors can be destructive. Fencing may be a feasible approach to reduce damage to small, targeted areas, and textural repellents may provide some utility to protect established trees. However, these non-lethal approaches will be marginally effective when beaver populations …

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Roof Rat Invasion Of An Urban Desert Island, Dale L. Nolte, David Bergman, John Townsend Mar 2003

Roof Rat Invasion Of An Urban Desert Island, Dale L. Nolte, David Bergman, John Townsend

United States Department of Agriculture Wildlife Services: Staff Publications

Roof rats have invaded the Phoenix metropolitan area. Although the desert surrounding Phoenix is formidacie to roof rats, residential and urban development has probably sufficiently altered habitat to render it suitable for roof rats. Ongoing community and government campaigns are reducing the resources necessary for rat survival and are working to suppress rat populations. Whether these efforts will be adequate to eradicate roof rats from the area is unknown. Rat activity has declined over the past several months. However, it is difficult to assess whether this reduced activity reflects decreased rat numbers or if rats have become less active during …

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Pre- And Post-Harvest Movements Of Female Rice-Field Rats In West Japanese Rice Fields, Jens Jacob, Dale L. Nolte, Rudy Hartono Mar 2003

Pre- And Post-Harvest Movements Of Female Rice-Field Rats In West Japanese Rice Fields, Jens Jacob, Dale L. Nolte, Rudy Hartono

United States Department of Agriculture Wildlife Services: Staff Publications

This study examined changes in the spatial behavior of rice-field rats (Rattus argentiventer) associated with the harvest of lowland irrigated rice. Radio-collared female rice-field rats were tracked before and after harvest in rice fields in West Java, Indonesia. The rice-field rats clearly reacted to the changes in habitat structure caused by the harvest by relocating their home ranges on average 300-400 m to piles of rice straw left on the fields and to unharvested areas. Post-harvest, there was a decrease in home-range size of 67% (0.6 ha pre-harvest: 0.2 ha post-harvest) and a decrease in range span of …

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Wariness Of Coyotes To Camera Traps Relative To Social Status And Territory Boundaries, E.S. Sequin, Michael M. Jaeger, Peter F. Brussard, Reginald H. Barrett Mar 2003

Wariness Of Coyotes To Camera Traps Relative To Social Status And Territory Boundaries, E.S. Sequin, Michael M. Jaeger, Peter F. Brussard, Reginald H. Barrett

United States Department of Agriculture Wildlife Services: Staff Publications

The primary objective of this study was to develop a better understanding of coyote (Canis latrans) wariness particularly as it related to social status. We determined that territory status (controlling alpha, resident beta, or nonterritorial transient) affected vulnerability to photo-capture by infrared-triggered camera systems. All coyotes were wary of cameras, leading to relatively low numbers of photo-captures, most of which occurred at night. Alphas were significantly underrepresented in photographs and were never photo-captured inside their awn territories. Betas were photographed inside and outside their territories, whereas transients were most often photographed on edges of territories. Both alphas and …

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Low Mitochondrial Dna Variation In Double-Crested Cormorants In Eastern North America, Juliann L. Waits, Michael L. Avery, Mark E. Tobin, Paul L. Leberg Feb 2003

Low Mitochondrial Dna Variation In Double-Crested Cormorants In Eastern North America, Juliann L. Waits, Michael L. Avery, Mark E. Tobin, Paul L. Leberg

United States Department of Agriculture Wildlife Services: Staff Publications

Double-crested Cormorant (Phalacrocorax auritus) numbers are increasing throughout eastern North America. We compared variation for five portions of mtDNA to determine if genetic differences existed among portions of the breeding range that would need to be considered when formulating management programs. Sequences for four mtDNA regions were identical across sample locations; frequencies of two haplotypes of the mitochondrial Control Region were similar across sampling locations. There is no evidence of restricted gene flow among breeding areas, or between subspecies with different migratory patterns.

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Scavenging By Vertebrates: Behavioral, Ecological, And Evolutionary Perspectives On An Important Energy Transfer Pathway In Terrestrial Ecosystems, Travis L. Devault, Olin E. Rhodes Jr., John A. Shivik Feb 2003

Scavenging By Vertebrates: Behavioral, Ecological, And Evolutionary Perspectives On An Important Energy Transfer Pathway In Terrestrial Ecosystems, Travis L. Devault, Olin E. Rhodes Jr., John A. Shivik

United States Department of Agriculture Wildlife Services: Staff Publications

Carrion use by terrestrial vertebrates is much more prevalent than conventional theory implies, and, rather than a curiosity of animal behavior, is a key ecological process that must be accounted for. Human aversion to rotted substances and difficulties associated with identifying scavenged material in studies of food habits have contributed to the relative lack of information concerning scavenging behavior in vertebrates. Several lines of evidence, however, suggest that carrion resources are more extensively used by vertebrates than has been widely assumed: 1) a substantial number of animals die from causes other than predation and become available to scavengers, 2) a …

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