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Population trends of North American sea ducks based on Christmas Bird Count and Breeding Bird Survey data

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Abstract

Due to the difficulty of conducting range-wide surveys of either breeding or wintering populations, few data are available to assess the population trends of sea ducks with confidence. We analyze sea duck data from the Audubon Christmas Bird Count (CBC) using hierarchical modeling methods that control for varying effort among circles and over time. These procedures allow us to assess early-winter relative density patterns among states and Bird Conservation Regions (BCRs) while also assessing trends in these regions and across the species North American range. Over the interval 1966-2003, continent-wide declines were observed in 1 of 11 species. Where sufficient data exist, we compare CBC results to estimates of population change derived from the USGS Breeding Bird Survey. The CBC does not effectively sample offshore populations of sea ducks; however, the CBC data can be used to assist in development of species-specific surveys, and CBC data can be used in combination with additional offshore sampling programs to better sample sea duck species.

Additional Publication Details

Publication type:
Book chapter
Publication Subtype:
Book Chapter
Title:
Population trends of North American sea ducks based on Christmas Bird Count and Breeding Bird Survey data
Year Published:
2005
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
123
Larger Work Type:
Book
Larger Work Subtype:
Other Government Series
Larger Work Title:
Second North American Sea Duck Conference, November 7-11, 2005, Annapolis, Maryland. Program and Abstracts
First page:
101 (abs)
Number of Pages:
123