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University of Nebraska - Lincoln

1997

Population

Articles 1 - 2 of 2

Full-Text Articles in Life Sciences

Nesting Populations Of Double-Crested Cormorants In The United States And Canada, Laura A. Tyson, Jerrold L. Belant, Francesca J. Cuthbert, D.V. (Chip) Weseloh Dec 1997

Nesting Populations Of Double-Crested Cormorants In The United States And Canada, Laura A. Tyson, Jerrold L. Belant, Francesca J. Cuthbert, D.V. (Chip) Weseloh

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Double-crested cormorants (Phalacrocorax auritus) are receiving increasing attention in North America because of depredations at aquaculture facilities and alleged impacts on sport and commercial fisheries. We obtained recent (most since 1994) estimates for the number of nesting double-crested cormorants in the United States and Canada from published references and by conducting telephone interviews with State and Provincial biologists. Using published data, we also determined annual rates of change in the number of cormorants since about 1990. The estimated minimum number of nesting pairs (colonies) of double-crested cormorants was 372,000 (852). Most cormorants nested in the Interior region (68 …


Changes In The Status, Distribution, And Management Of Double-Crested Cormorants In Wisconsin, Summer W. Matteson, Paul W. Rasmussen, Kenneth L. Stromborg, Thomas I. Meier, Julie Van Stappen, Eric C. Nelson Dec 1997

Changes In The Status, Distribution, And Management Of Double-Crested Cormorants In Wisconsin, Summer W. Matteson, Paul W. Rasmussen, Kenneth L. Stromborg, Thomas I. Meier, Julie Van Stappen, Eric C. Nelson

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

We reviewed and summarized historical data and conducted population surveys from 1973 through 1997 to determine the breeding status and distribution of doublecrested cormorants (Phalacrocorax auritus) in Wisconsin. Breeding cormorants historically occupied large, isolated lakes and wetlands in northern Wisconsin, but there were no known nesting sites until 1919, when cormorants were reported nesting on Lake Wisconsin in south-central Wisconsin. From the 1920’s to the 1950’s, cormorants occupied 17 colony sites in 16 counties, though no more than 7 sites were occupied during any particular year. From the 1950’s to the early 1970’s, the number of cormorant nests …