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Full-Text Articles in Life Sciences

Wintering Ecology Of Adult North American Ospreys, Brian E. Washburn, Charles J. Henny, Mark S. Martell, Richard O. Bierregaard, Brian S. Dorr, Thomas J. Olexa Dec 2014

Wintering Ecology Of Adult North American Ospreys, Brian E. Washburn, Charles J. Henny, Mark S. Martell, Richard O. Bierregaard, Brian S. Dorr, Thomas J. Olexa

Brian S Dorr

North American Ospreys (Pandion haliaetus) typically migrate long distances to their wintering grounds in the tropics. Beyond the general distribution of their wintering range (i.e., the Caribbean, South America, and Central America), very little is known about the wintering ecology of these birds. We used satellite telemetry to determine the duration of wintering period, to examine the characteristics of wintering areas used by Ospreys, and to quantify space use and activity patterns of wintering Ospreys. Adult Ospreys migrated to wintering sites and exhibited high wintering site fidelity among years. Overall, Ospreys wintered on river systems (50.6%) more than on lakes …


Geographic Segregation And Evidence Of Density-Dependent Changes In Sex Ratios In An Abundant Colonial Waterbird, Brian S. Dorr, Katie C. Hanson-Dorr, Travis L. Devault, Alban Guillaumet, Scott C. Barras Dec 2014

Geographic Segregation And Evidence Of Density-Dependent Changes In Sex Ratios In An Abundant Colonial Waterbird, Brian S. Dorr, Katie C. Hanson-Dorr, Travis L. Devault, Alban Guillaumet, Scott C. Barras

Brian S Dorr

Demographic information, such as geographic segregation of sexes and sex ratio data, is needed to develop, model and evaluate conservation and management strategies for wildlife. A variety of physiological, behavioral and environmental factors can influence segregation of sexes and sex ratios, many of which originate with density- dependent processes. Departure from 50:50 sex ratios of double-crested cormorants (Phalacrocorax auritus) collected during control efforts in breeding and wintering areas across their eastern range of the USA were evaluated using using a Z-test as well as Stouffer’s weighted Z-tests. In addition, a specifically-designed randomization test was used to evaluate density-dependent effects on …


The Cumulative Effects Of Management On The Population Dynamics Of The Double-Crested Cormorant Phalacrocorax Auritus In The Great Lakes, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Terry J. Doyle Jan 2014

The Cumulative Effects Of Management On The Population Dynamics Of The Double-Crested Cormorant Phalacrocorax Auritus In The Great Lakes, Alban Guillaumet, Brian S. Dorr, Guiming Wang, Terry J. Doyle

Brian S Dorr

Wildlife species have been subject to control efforts throughout human history due to real or alleged human–wildlife conflicts. The Double-crested Cormorant Phalacrocorax auritus in the interior of North America is no exception, with recent population growth leading to increased conflicts and consequently the development of many control programmes. These control programmes are usually conducted at local scales, often with little or no effort to assess their cumulative effects at the population level. We attempted the first comprehensive assessment of the cumulative effects of control at various spatio-temporal scales, focusing on 199 colonies of Double-crested Cormorant monitored during a 29-year period. …