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United States Department of Agriculture Wildlife Services: Staff Publications

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Articles 1501 - 1529 of 1529

Full-Text Articles in Physical Sciences and Mathematics

Diversity: How To Lie With Biodiversity, Gordon H. Rodda Dec 1993

Diversity: How To Lie With Biodiversity, Gordon H. Rodda

United States Department of Agriculture Wildlife Services: Staff Publications

Biodiversity is the bandwagon of the moment. Unfortunately, the concept is sufficiently complex that almost any population biology study, with almost any conclusion, can be framed as an effort to measure or conserve biodiversity. Based on what 1 have seen in the literature and heard at recent scientific meetings, here is a primer on some of the more popular ways to bend biodiversity data.

Suppose you wish to claim that a species is disappearing. With the explanation that time and funding were limited, you might present population trajectories based on as few as two estimates of abundance. Perhaps the final …

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Migration And Dispersal Of Laughing Gulls In The United States, Jerrold L. Belant, Richard A. Dolbeer Sep 1993

Migration And Dispersal Of Laughing Gulls In The United States, Jerrold L. Belant, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

The 3662 recovery records for Laughing Gulls (Larus atriczlla) banded in North America from 1924 to 1991 were analyzed to determine migration and dispersal patterns for Northeast (Maine to Virginia) and Gulf Coast (west coast of Florida to Texas) populations. Autumn migration for Northeast Laughing Gulls was initiated in October. Northeast Laughing Gulls migrated greater distances and were recovered farther south during winter than Gulf Coast gulls. Significantly more Gulf Coast Laughing Gulls wintered along the Gulf Coast than did Northeast Laughing Gulls. In contrast, significantly more Northeast Laughing Gulls wintered in Central and South America. Adult Laughing Gulls returned …

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Toward Conservation Of Midcontinental Shorebird Migrations, Susan K. Skagen, Fritz L. Knopf Sep 1993

Toward Conservation Of Midcontinental Shorebird Migrations, Susan K. Skagen, Fritz L. Knopf

United States Department of Agriculture Wildlife Services: Staff Publications

Shorebirds represent a highly diverse group of species, many of which experience tremendous energy demands associated with long-distance migratory flights. Transcontinental migrants are dependent upon dynamic freshwater wetlands for stopover resources essential for replenishment of lipid reserves and completion of migration. Patterns of shorebird migration across midcontinental wetlands were detected from migration reports to American Birds and information provided by U.S. Fish and Wildlife Service national wildlife refuges. Patterns in species composition and abundance varied geographically, emphasizing the uniqueness of different regions to migrating shorebirds. Smaller species and neotropical migrants moved primarily across the Great Plains, whereas larger species and …

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Animal Welfare And The Statistical Consultant, Richard M. Engeman, Stephen A. Shumake Aug 1993

Animal Welfare And The Statistical Consultant, Richard M. Engeman, Stephen A. Shumake

United States Department of Agriculture Wildlife Services: Staff Publications

Animal welfare considerations and regulations serve to ensure that experimental animals are used wisely while minimizing stress. Substantial impacts on the use of animals in experiments have resulted, thereby increasing the challenges for designing studies and analyzing data to provide valid inferences. Statisticians should become more indispensable for involvement in study design (including Animal Care and Use Committees), application of appropriate analyses, prudent interpretation of results, and the development of new statistical techniques to meet these needs.

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Short Courses As Part Of Statistical Consulting In A Foreign Setting, Richard M. Engeman May 1993

Short Courses As Part Of Statistical Consulting In A Foreign Setting, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

It is common for many consulting statisticians to provide statistical training to their clients. The number and depth of potential difficulties that can arise when giving a short course are greatly increased when the course is given in a foreign setting. Recommendations and examples are given for overcoming these difficulties and for efficient presentation of the course material.

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Effects Of Predator Odors On Feeding In The Mountain Beaver (Aplodontia Rufa), Gisela Epple, J. Russell Mason, Dale L. Nolte, Dan L. Campbell Jan 1993

Effects Of Predator Odors On Feeding In The Mountain Beaver (Aplodontia Rufa), Gisela Epple, J. Russell Mason, Dale L. Nolte, Dan L. Campbell

United States Department of Agriculture Wildlife Services: Staff Publications

Consumption of food by Aplodontia rufa from bowls scented with control odors, secretion from anal glands of minks (Mustela vison), or urine from minks, bobcats (Felis rufus), and coyotes (Canis latrans) was studied. In two-choice control tests, subjects indiscriminately consumed apple from unscented bowls and from bowls scented with urine from an unfamiliar herbivore (Cavia porcellus), or with butyric acid. During two-choice tests offering apple from bowls scented with secretion from anal glands of minks and from bowls scented with butyric acid, significantly less apple was consumed from bowls containing mink scent. …

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Migration Patterns Of Double-Crested Cormorants East Of The Rocky Mountains, Richard A. Dolbeer Jan 1991

Migration Patterns Of Double-Crested Cormorants East Of The Rocky Mountains, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

The 5589 recovery records for Double-crested Cormorants (Phalacrocorax auritus) banded in North America from 1923 to 1988 were analyzed to determine migration patterns and the source of populations wintering in the lower Mississippi Valley and Gulf of Mexico coastal region. Autumn migration from areas north of latitude 42°N primarily occurred in October and November. Spring migration occurred mainly in April for birds >2 yr old and in May for birds <1 yr old. During summer,1-yr-old birds were recovered significantly farther from their natal colony than were older birds. Cormorants nesting in Canada and the northern United States from Alberta to the Gulf of St. Lawrence migrated in winter primarily to the southern United States between Texas and Florida. There was considerable mixing and overlap in winter of nesting populations from widely divergent areas. From 38 to 70% of the birds from Saskatchewan throughout the Great Lakes region were recovered in the lower Mississippi Valley as were 10% of the birds from such disparate areas as Alberta and the New England coast. There was little mixing of populations from east and west of the Rocky Mountains.

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Disappearance And Recoverability Of Songbird Carcasses In Fruit Orchards, Mark E. Tobin, Richard A. Dolbeer Jun 1990

Disappearance And Recoverability Of Songbird Carcasses In Fruit Orchards, Mark E. Tobin, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Songbird mortality due to agricultural pesticides is often assessed by searching treated areas for carcasses. However, carcass removal by scavengers and the failure of searchers to find carcasses that are present may bias mortality estimates. We conducted two studies in 1987 and 1988 in New York to evaluate such biases at the time of fruit maturation in cherry and apple orchards. In the first study, mean survival times for carcasses were 8.2 d in cherry and 10.4 d in apple orchards. In the second study, searchers located an average of 75% of carcasses placed in orchards. Our results suggest that …

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Alternatives To Fisher's "Exact Test" For Analyzing 2 X 2 Tables With Small Cell Sizes, Richard M. Engeman Mar 1990

Alternatives To Fisher's "Exact Test" For Analyzing 2 X 2 Tables With Small Cell Sizes, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

Rice (1988a) presents an interesting test for analyzing 2 X 2 contingency tables in the smaller sample size situations. His motivation was to provide an alternative to Fisher's "exact test" and his rationale was based on the application of a prior distribution to the probability of a success, 0, under the null hypothesis. We would like to briefly comment on these aspects of his paper and also discuss another alternative that was proposed a number of years ago.

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Boreal Toad In Clear Creek County, Colorado, Richard M. Engeman, Robert W. Connell Feb 1990

Boreal Toad In Clear Creek County, Colorado, Richard M. Engeman, Robert W. Connell

United States Department of Agriculture Wildlife Services: Staff Publications

Many amphibian populations worldwide have experienced recent population declines (e.g. Barinaga 1990). Included among these are declines for the boreal toad (Bufo boreas boreas) in the central Rocky Mountains (Corn et al. 1989; Stolzenburg 1989). The extent of the population declines is such that boreal toad populations in the Rocky Mountains have been included on the list of species to be reviewed by the U.S. Fish and Wildlife Service for Threatened or Endangered status (Federal Register 1989). We report here an additional population site for the boreal toad in Colorado.

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Herring Gulls, Larus Argentatus, Nesting On Sandusky Bay, Lake Erie, 1989, Richard A. Dolbeer, P.P. Woronecki, T. W. Seamans, B. N. Buckingham, E. C. Cleary Oct 1989

Herring Gulls, Larus Argentatus, Nesting On Sandusky Bay, Lake Erie, 1989, Richard A. Dolbeer, P.P. Woronecki, T. W. Seamans, B. N. Buckingham, E. C. Cleary

United States Department of Agriculture Wildlife Services: Staff Publications

One of the largest herring gull (Larus argentatus} nesting populations on the Great Lakes is located in an urban setting on Sandusky Bay in the Ohio portion of Lake Erie. The survey reported here, carried out in 1989, indicated a population of 4,250 nests. The population has expanded from a focal point on Turning Point Island to coal piles at the Lower Lake Dock Company, rooftops in downtown Sandusky and breakwalls near Cedar Point. Comparison with data from a survey performed in 1976 indicates the population has grown at an average annual rate of 11.9% during the past 13 years. …

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Biochemical And Morphological Characteristics In Maturing Achenes From Purple-Hulled And Oilseed Sunflower Cultivars, Roger W. Bullard, Paul P. Woronecki, Richard A. Dolbeer, J. Russell Mason Jan 1989

Biochemical And Morphological Characteristics In Maturing Achenes From Purple-Hulled And Oilseed Sunflower Cultivars, Roger W. Bullard, Paul P. Woronecki, Richard A. Dolbeer, J. Russell Mason

United States Department of Agriculture Wildlife Services: Staff Publications

The blackbird feeding preference for sunflower oilseed variety Jacques Discovery (JD) over purple-hulled Neagra de Cluj (NdC) has been attributed to anthocyanin. To test this hypothesis, we compared biochemical and morphological properties in the achene over the maturation period. Comparisons included total phenols, anthocyanin, tannin, fat/oil, protein, nonstructural sugars, and phytomelanin contents, as well as mass properties and moisture content. Only three differences were observed: (1) Hull mass was significantly higher for NdC than JD. (2) Anthocyanins were synthesized by NdC only. (3) JD was higher in oil content. Each of these factors may play a role in reduced preferences …

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The Use Of Banding Recovery Data To Estimate Dispersal Rates And Gene Flow In Avian Species: Case Studies In The Red-Winged Blackbird And Common Grackle , William S. Moore, Richard A. Dolbeer Jan 1989

The Use Of Banding Recovery Data To Estimate Dispersal Rates And Gene Flow In Avian Species: Case Studies In The Red-Winged Blackbird And Common Grackle , William S. Moore, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Dispersal resulting in gene flow strongly affects the evolution of genetic structure in populations. This report describes statistical estimators of dispersal parameters based on USFWS banding recovery records. Finite-area studies of avian species yield estimates of root-mean-square (RMS) dispersal along a transect of about 1 km per generation. In contrast, estimates of RMS dispersal for the Red-winged Blackbird (Agelaiusp hoeniceus) and Common Grackle (Ouiscalus auiscula), based on USFWS banding recovery records, are 94.6 and 111.4 km per generation, respectively. Distributions for both species are extremely leptokurtic, and confidence intervals based on jackknife statistics are large because the estimators are sensitive …

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Expected Mean Squares On Ms-Dos, Richard M. Engeman, Amber D. Lusk Aug 1988

Expected Mean Squares On Ms-Dos, Richard M. Engeman, Amber D. Lusk

United States Department of Agriculture Wildlife Services: Staff Publications

An interactive program for calculating the expected mean squares for balanced designs was developed for use on a Tektronix 4054 desktop computer (Engeman 1982). That program used BASIC string commands that did not translate well into other forms of BASIC, including that for MS-DOS machines. The program has since been rewritten to run on MS-DOS machines. Its output has also been expanded. The new version was written in BASIC on an AT&T PC 6300 and will run on most MS-DOS machines that support BASIC.

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Nonparametric Comparison Of Exponential Growth Curves, Russel S. Rickard, Richard M. Engeman, Gary O. Zerbe Aug 1988

Nonparametric Comparison Of Exponential Growth Curves, Russel S. Rickard, Richard M. Engeman, Gary O. Zerbe

United States Department of Agriculture Wildlife Services: Staff Publications

A program to compare exponential growth curves via randomization tests has been developed for the one-way analysis-of variance situation. Exponential growth curves of the form Y = a - b exp( - gt) are first fit to each individual's longitudinal data. The parameters from each individual's curve are then input into the randomization program.

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Blackbird And Starling Feeding Behavior On Ripening Corn Ears, Glen E. Bernhardt, Lynda Van Allsbur, Richard A. Dolbeer Jan 1987

Blackbird And Starling Feeding Behavior On Ripening Corn Ears, Glen E. Bernhardt, Lynda Van Allsbur, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

The behavior of red-winged blackbirds {Agelaius phoemcei/s), common grackles (Quiscalus quiscula), brown-headed cowbirds (Molothrus ater), and juvenile European starlings (Sturnus vulgaris) feeding on ears of corn was studied in an aviary. The species differed significantly in their propensity to attack (penetrate the husk and feed on kernels) ears of corn. Redwings and starlings were more active attackers than grackles and cowbirds. Female redwings were generally more active attackers than males, but less efficient at opening husks and damaging ears. Redwings and starlings used primarily the gaping technique to penetrate husks and expose kernels. Redwings more commonly penetrated the side of …

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Habitat Suitability Index Models: Snowshoe Hare, R.G. Carreker Aug 1985

Habitat Suitability Index Models: Snowshoe Hare, R.G. Carreker

United States Department of Agriculture Wildlife Services: Staff Publications

This document is part of the Habitat Suitability Index (HSI) Model Series [Biological Report 82(10)] which provides habitat information useful for impact assessment and habitat management. Several types of habitat information are provided. The Habitat Use Information Section is largely constrained to those data that can be used to derive quantitative relationships between key environmental variables and habitat suitability. This information provides the foundation for the HSI model and may be useful in the development of other models more appropriate to specific assessment or evaluation needs.

The HSI Model Section documents the habitat model and includes information pertinent to its …

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Sex-Specific Feeding Habits Of Brown-Headed Cowbirds In Northern Ohio In January, Richard A. Dolbeer, Cynthia R. Smith Jan 1985

Sex-Specific Feeding Habits Of Brown-Headed Cowbirds In Northern Ohio In January, Richard A. Dolbeer, Cynthia R. Smith

United States Department of Agriculture Wildlife Services: Staff Publications

We examined the stomach contents of 57 brown-headed cowbirds (Molothrus ater) collected from a roost in Erie Co., Ohio, on 12 January 1983. Corn was by far the predominant food, averaging 66% of the stomach contents by weight. Seeds from at least five grasses, but primarily Setaria spp., were the second most abundant food category, averaging 21% of the stomach contents. Ragweed {Ambrosia artemisiifolia) seeds (2.6%) were third. Male cowbirds consumed more corn than did the smaller females, whereas females consumed more of the smaller grass seeds. The abundance of corn in harvested fields and feedlots, combined with mild winter …

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Statistical Consulting In A Geographically Dispersed Organization, Richard M. Engeman, William E. Dusenberry Nov 1984

Statistical Consulting In A Geographically Dispersed Organization, Richard M. Engeman, William E. Dusenberry

United States Department of Agriculture Wildlife Services: Staff Publications

There has been much discussion in the recent statistical literature concerning the optimal manner for a consulting statistician to operate within a larger organization. Marquardt (1979) described the "total involvement" approach, involving a statistician from conceptualization of a project to the final report; Finney (1982) discussed the questions a statistician should ask for effective consulting; and Bishop, Peterson, and Tragser (1982) argued that a statistician's most substantive contributions are made during the planning stages of a study. McCulloch et al. (1982) described a program for training statistical consultants, and Hunter (1981) discussed the roles a statistician may assume.

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Survival Analysis For A Red Squirrel Population, Curtis H. Halvorson, Richard M. Engeman May 1983

Survival Analysis For A Red Squirrel Population, Curtis H. Halvorson, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

A 13-year study of an isolated red squirrel (Tamiasciurus hudsonicus) population in Montana has provided the data necessary to analyze their survival. Such long-term, intensive studies of wild populations are rare. When reported, derived (ratio) estimates are used to develop survival information as Gross et al. (1974), and Keith and Windberg (1978) did in respective 9- and 15-year lagomorph studies. A more accurate method, following cohorts, was used by Armitage and Downhower (1974) and Mosby (1969), who presented results for six or more year-classes of sciurids in actuarial tables (Deevey, 1947; Allee et al., 1949).

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Expected Mean Squares, Richard M. Engeman Aug 1982

Expected Mean Squares, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

An interactive program for calculating the expected mean squares for balanced designs has been developed for use on desktop and minicomputers, where it would be most convenient for the typical applications of the consulting statistician. The theoretical expected mean squares are calculated from the ANOVA model; hence, data are not utilized.

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Migration Patterns For Age And Sex Classes Of Blackbirds And Starlings, Richard A. Dolbeer Mar 1982

Migration Patterns For Age And Sex Classes Of Blackbirds And Starlings, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Red-winged Blackbirds (Agelaius phoeniceus), Brown-headed Cowbirds (Molothrus ater), and Starlings (Sturnus vulgaris) are ubiquitous breeding birds in much of North America. The Common Grackle (Quiscalus quiscula) is an abundant breeding bird east of the Rocky Mountains (Dolbeer and Stehn 1979). Although these species are widely dispersed and generally unassociated during the nesting season, they often associated closely in winter roosts containing up to 10 million birds in the southern United States (Meanley and Webb 1965, Meanley 1971). Little is known about the comparative migration patterns of the four species and the resulting mixture of local breeding populations in winter. Comparative …

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In Search Of A Diversity Ethic For Wildlife Managemen, Fred B. Samson, Fritz L. Knopf Jan 1982

In Search Of A Diversity Ethic For Wildlife Managemen, Fred B. Samson, Fritz L. Knopf

United States Department of Agriculture Wildlife Services: Staff Publications

As the century nears its end and demand for food and competition for land escalate, a most important issue facing conservationists will be the preservation of a mosaic of habitats in which can be preserved a representative cross-section of native species. The need to resolve this issue is emphasized in the Global 2000 Report to the President (Council on Environmental Quality 1980) which predicts that, worldwide, 500,000 to 2 million species will become extinct by the year 2000 and that the rate will increase from one per day in 1980 to one per hour by century's end (Myers 1979). Although …

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Blackbirds And Corn In Ohio, Richard A. Dolbeer Feb 1980

Blackbirds And Corn In Ohio, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Damage to corn by blackbirds (Icteridae) has been an economic problem throughout historical times in North America. Ohio, with the highest nesting season population density of red-winged blackbirds (Agelaius phoeniceus) in North America and large acreages of corn, has been a key state in this conflict. Survey of damage from 1968 to 1979 revealed that blackbirds annually destroyed less than 1% of the corn crops in Ohio, a 4- to 6-million dollar loss at 1979 prices. This total dollar loss is somewhat misleading because of the uneven distribution of damage among fields. Over 97% of the cornfields in …

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Compensatory Response Of Maturing Corn Kernels Following Simulated Damage By Birds, Paul P. Woronecki, Robert A. Stehn, Richard A. Dolbeer Jan 1980

Compensatory Response Of Maturing Corn Kernels Following Simulated Damage By Birds, Paul P. Woronecki, Robert A. Stehn, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

(1) A study was made to measure compensatory growth responses and to estimate losses associated with bird damage to maturing corn.
(2) Corn kernels contain 20-40% of their final biomass at the time they are usually consumed by blackbirds.
(3) Very slight compensation of kernel weight occurred following simulated bird damage to tip kernels.
(4) Heavy bird damage, early in kernel development, increased fungal, sprouting, and insect damage before harvest.
(5) Estimates of bird damage, subsequent secondary damage, and compensation were affected by the amount of damage, maturity of the kernels at the time of damage, and environmental factors before, …

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Agricultural Impact Of A Winter Population Of Blackbirds And Starlings, Richard A. Dolbeer, Paul P. Woronecki, Allen R. Stickley Jr., Stephen B. White Mar 1978

Agricultural Impact Of A Winter Population Of Blackbirds And Starlings, Richard A. Dolbeer, Paul P. Woronecki, Allen R. Stickley Jr., Stephen B. White

United States Department of Agriculture Wildlife Services: Staff Publications

The major concentration of blackbirds and Starlings (Sturnus vulgaris) in North America occurs in the southeastern United States where an estimated 350 million Red-winged Blackbirds (Agelaius phoeniceus) , Common Grackles (Quiscalus quiscula) , Brown-headed Cowbirds (Molothrus ater) , and Starlings congregate in winter roosts (Meanley 1971, 1975, 1977). An estimated 75-100 major (containing >l million birds) roosts form in the southeastern states each year. Increasing attention is being given to many of these roosts because of nuisance problems, reputed health hazards, and agricultural damage associated with them. Although considerable effort has been directed toward developing methods for reducing roosting populations …

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Movement And Migration Patterns Of Red-Winged Blackbirds: A Continental Overview, Richard A. Dolbeer Jan 1978

Movement And Migration Patterns Of Red-Winged Blackbirds: A Continental Overview, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

From 1924 through 1974, about 11,000 recoveries accumulated from the banding of over 700,000 Red-winged Blackbirds(Agelaius phoeniceus) in North America. A few studies have examined some of these data for specific localities during certain times of the year; however, no attempt has been made to examine the total recovery data to compile a general picture of continental movement and migration patterns. Increasing attention is being given to blackbird (Icteridae) and Starling (Sturnus vulgaris) populations in North America because of their reported crop depredations, health hazards, and nuisance aspects, especially when congregating in large roosts (Meanley,1975;Graham, 1976). Solutions to these problems …

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Reproduction In The Red Squirrel (Tamiasciurus Hudsonicus) In Colorado, Richard A. Dolbeer May 1973

Reproduction In The Red Squirrel (Tamiasciurus Hudsonicus) In Colorado, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Information on reproduction of the red squirrel (Tamiasciumrs hudsonicus) can be gleaned from studies in the northeastern United States (Klugh, 1927; Hamilton, 1939; Layne, 1954) and in western Canada (Miller, 1970; Smith, 1968; Kemp and Keith, 1971; Wood, 1967). However, there is a paucity of information on reproduction from the mountainous regions of the western United States. This paper presents reproductive information on the red squirrel from Colorado and helps fill this void. In addition, the reproductive strategy of red squirrels is briefly compared with that of snowshoe hares.

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Winter Behavior Of The Eastern Box Turtle, Terrapene C. Carolina L., In Eastern Tennessee, Richard A. Dolbeer Jan 1970

Winter Behavior Of The Eastern Box Turtle, Terrapene C. Carolina L., In Eastern Tennessee, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

A field study of winter movements and depths and types of hibernacula of the eastern box turtle, Terrapene carolina carolina L., was undertaken from October 1968-January 1969.

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