The 2010 North American trumpeter swan survey. A cooperative North American survey

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The North American trumpeter swan survey has been conducted approximately every 5 years since 1968 to assess the abundance, productivity, and distribution of trumpeter swans (Cygnus buccinator) in North America. The 2010 quinquennial survey was conducted May 2010–January 2011 by cooperators throughout Canada and the northern United States. Methods in 2010 varied among regions but were generally similar to prior surveys within regions. Notable exceptions included a change from complete censuses to stratified random sampling in Alaska and parts of Canada. Most cooperators performed aerial surveys, ground counts, or a combination of the two. The 2010 continental estimate of trumpeter swan abundance was 46,225 (SE = 1,172), an increase of 33% since 2005 and the highest recorded since the surveys began in 1968. The estimated average annual growth rate was +6.2% (P < 0.0001) during 1968–2010 and +5.8% during 2005–2010. Cygnets comprised 26% of the total population in 2010. Each of North America’s three recognized trumpeter swan populations reached record-high abundance levels in 2010. The 2010 total swan abundance estimates and percent changes from 2005 for the Pacific Coast, Rocky Mountain, and Interior populations were 26,790 (SE = 1,060) (+7%), 9,626 (SE = 500) (+84%), and 9,809 (+111%), respectively. Estimates of average annual growth rates and indices of production are presented for the three populations and their component flocks.

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ELECTRONIC FILE - Zoology: Birds

Full citation: Groves, Deborah J., compiler. 2012. The 2010 North American trumpeter swan survey: a cooperative North American survey. U. S. Fish and Wildlife Service, Division of Migratory Bird Management, Juneau, AK. 17 p. + appendices.

SWAP (2/19/2016) citation (with author descriptor provided):
Groves DJ, compiler. 2012. The 2010 North American trumpeter swan survey. A cooperative North American survey. Juneau (AK): US Fish and Wildlife Service, Migratory Bird Management Division. 17 p