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North American Breeding Bird Survey annual summary 1990-1991

Bird Populations

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Abstract

The North American Breeding Bird Survey (BBS) was used to estimate continental and regional changes in bird populations during 1989-1990 and 1990-1991, placing these short-term changes within the context of population trends since 1966. For the entire survey area, 51.7% of the species exhibited increases in population size during 1989-1990, reversing the decreasing tendency exhibited by the majority of species during 1988-1989. A similar percentage (51.4%) of species with increasing populations was noted during 1990-1991. These percentages were also analyzed for 12 guilds of North American birds and 3 broad geographical regions. Many regional patterns exist in these population changes, reflecting the variability inherent in short-term population fluctuations. Two-year (1989-1990 and 1990-1991) changes and long-term (1966-1990) continental trends are provided for 255 species.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
North American Breeding Bird Survey annual summary 1990-1991
Series title:
Bird Populations
Volume
1
Year Published:
1993
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
52-67
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bird Populations
First page:
52
Last page:
67
Number of Pages:
16