Use of ratio estimators to estimate the size of common eider populations in winter

Article Abstract:

Surveys of the abundant common eider duck are usually conducted during winter because their numbers are easier to assess when they gather in small, discrete areas. Until now, population size estimates have been based on visual data, which may be unreliable. A new method of surveying eiders in Quebec uses a three-step, model-based ratio estimator process to estimate population size. The study shows significant differences between photo counts and visual estimates. It is suggested that the exclusive use of visual estimates to monitor duck numbers during winter is unacceptable.

Models, Observations, Natural history, Eider, Quebec, Bird populations

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Finding common ground: conservationists and regulated interests pursue ESA reform together

Article Abstract:

Collaboration between conservationists and regulated community parties is essential to ensure reauthorization of the Endangered Species Act. The reform proposals formulated by the two groups enhance conservation and protection of endangered, declining and threatened species. The new dimensions proposed include federal agency's role in making recovery plans and avoiding jeopardy to species. There is a provision for improving habitat based planning to protect and restore ecosystems, and natural communities.

Beliefs, opinions and attitudes, Conservationists

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Winter in the Bahamas may be no vacation for Kirtland's warbler

Article Abstract:

Analyses of reports on the wintering habitat of the endangered Kirtland's warbler, or Dendroica kirtlandii, which have been compiled since 1841 were conducted. It was widely believed that the wintering grounds of Dendroica kirtlandii was low scrub which grew in abundance in the Bahamas. However, results of a study using acoustic playback showed that the birds thrived in pine ecosystems.

Environmental aspects, Birds, Bahamas, Animal wintering, Kirtland's warbler

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