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Browsing Researcher Spotlights by Author "Cooch, E.G."
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Item Open Access Site fidelity of Black Brant wintering and spring staging in the Strait of Georgia, British Columbia.(University of California Press, 1998-08) Reed, E.; Cooch, E.G.; Goudie, R.I.; Cooke, F.Site fidelity has important implications for population genetics and dynamics. In birds, most studies have dealt with breeding ground fidelity, ignoring the fact that waterfowl mainly pair in winter or early spring. We used multiple observation data from a mark-relight study of Black Brant (Branta bernicla nigricans) to estimate fidelity to wintering and spring staging areas in Boundary Bay and Parksville-Qualicum British Columbia. Site fidelity was low for winter residents but still indicated that Brant were faithful to Boundary Bay. Birds seen twice or more during any given winter had significantly higher site fidelity rates than those seen only once. The models for the spring period showed the presence of transients in both Boundary Bay and Qualicum. Birds seen for the first time in an area had a lower probability of returning to that area than birds seen in more than one year. Survival probability was significantly higher for Qualicum birds than for Boundary Bay birds. We concluded that prior knowledge of an area was an important determinant of site fidelity, and that low site fidelity levels were unlikely to lead to genetic sub structuring of the population.Item Open Access Survival rates for Cassin's and Rhinoceros Auklets at Triangle Island, British Columbia.(University of California Press, 2000-02) Bertram, D.F.; Jones, I.L.; Cooch, E.G.; Knechtel, H.A.; Cooke, F.We estimated survival of Cassin's Auklet (Ptychoramphus aleuticus) and Rhinoceros Auklet (Cerorhincam onocerata) from recapture rates during 1994-1997. For both species, a two "age"-class model provided the best fit. Estimates of local adult survival were significantly lower for Cassin's Auklet (0.672 +/- 0.047) than for Rhinoceros Auklet (0.829 +/- 0.095). Our estimate of survival appears lower than that required for the maintenance of a stable population of Cassin's Auklets. The available information indicates that a low survival rate and a declining population at Triangle Island are plausible, particularly given the recent age scale oceanographic changes which have occurred in the North Pacific Ocean. Nevertheless, additional mark-recapture data and indexes of population size are required to rigorously demonstrate population declines at the world's largest Cassin's Auklet colony.