European Shag (Phalacrocorax aristotelis) Science Article 5 abstract We compared morphometrics and discriminant functions for sexing European Shags Phalacrocorax aristotelis in a central (British) population and a peripheral (NW Iberia) population within its distribution range, to account for structural differences between populations and sexes. Overall, British shags were structurally larger than Iberian shags, except in […]

European Shag (Phalacrocorax aristotelis) Science Article 4 abstract While age related improvements in breeding success have been reported in many avian species, the underlying mechanisms are not well understood. Ectoparasite load can have a significant deleterious effect on many aspects of host fitness. If younger breeders carry high parasite loads, and this has a detrimental […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 10 abstract The breeding colony of the Double-crested Cormorant (Phalacrocorax auritus) on East Sand Island in the Columbia River estuary has grown dramatically over the last 13 years, in contrast to declines at other colonies along the coast of the Pacific Northwest. Immigration from other colonies has occurred and […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 18 abstract The objectives for this study were to: 1) determine the diet of Double-crested Cormorants (Phalacrocorax auritus, hereafter: cormorants) in western Lake Erie; 2) to determine if yellow perch (Perca flavescens) or walleye (Sander vitreus) were a noteworthy prey item; and 3) to determine if the invasive round […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 17 abstract The nesting colony of Double-crested Cormorants, Phalacrocorax auritus (Lesson, 1831), on East Sand Island in the Columbia River estuary is currently the largest for this species on the Pacific Coast of North America. We used radiotelemetry to investigate the spatial and temporal foraging patterns of nesting cormorants […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 15 abstract The ability to determine the age of birds accurately from their skeletons would be useful not only for population biology and wildlife management research but for avian palaeontological and archaeological analyses as well. While accurate osteologically based age determination techniques are available for some amphibians and reptiles […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 16 abstract Double-crested Cormorants (Phalacmcorax avril us) are normally considered a diurnal species. Herewe describe cormorants foraging nocturnally in an oxbow lake in Mississippi. We have observed this behavior onlyonce during 30 capture attempts over seven years. D. Tommy King, J. Brent Harrf, Brian Dorr and David Reinhoid, Colonial […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 9 abstract Kleptoparasitism, or the stealing of resources, has been observed within and betweenmany bird species (Brockmann and Barnard 1979, Furness and Monaghan 1987).Although the kleptoparasite sometimes steals food without aggression towards the host,the host may be threatened or even attacked (Brockmann and Barnard 1979). In thisnote, I report […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 12 abstract During the summer of 1998, the New York State Department of Environmental Conservation (NYSDEC) and the United States Geological Survey (USGS) conducted 11 studies designed to evaluate the impact of double-crested cormorant predation on smallmouth bass and other fish populations in the New York waters of the […]

Double-crested Cormorant (Phalacrocorax auritus) Science Article 8 abstract In North America, the Double-crested Cormorant (Phalacrocorax auritus) is currently abundant, widely distributed across five broad geographic regions, and often perceived as overabundant. In many U.S. states and Canadian provinces, policy makers are pressured to significantly reduce cormorant numbers, primarily to minimize conflicts between cormorants and fish […]