US Fish & Wildlife Service
Date of this Version
11-30-2011
Citation
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Abstract
Observers counted 480 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2011, 4.3% decrease from last years count (484). The number of white birds in the Tri-state region (354) decreased from last year’s count of 375. The total number of cygnets decreased 16.8%, from 107 in 2010 to 89 in 2011. Cygnet counts decreased from 2010 by 58.6% and 22.9% for Idaho and Wyoming respectively, while Montana cygnet production increased by 33%. Malheur National Wildlife Refuge (NWR) accounted for 5 swans this year which was up from last year. Seventeen swans were observed at the Summer Lake Wildlife Management Area, and increase from 11 last year. Nevada counted 15 swans on this year’s survey. Precipitation throughout most of the Tri-state Area was average during winter 2010 - 2011. During the summer months, temperatures were slightly below average and precipitation was above average, especially during June - August. Palmer Drought Indices for areas within the Tri-state region improved again for the second year in a row.
Comments
U. S. government work.