US Fish & Wildlife Service
Date of this Version
12-22-2009
Citation
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Abstract
Observers counted 473 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2009, 3.1% higher than the count from last year (459). The number of white birds in the tri-state region (361) decreased for the second year in a row from the recent high count in 2007 (383). The total number of cygnets increased by 3.1% from 2008. The numbers of young produced in Montana and Idaho increased by 66.7% and 76.2%, respectively, from 2008. However, Wyoming had a decrease in cygnet production of 9.1% from that of 2008. The abundance of total swans at Malheur National Wildlife Refuge (NWR) was half of what it was in 2008. However, the survey was incomplete because no aircraft were available to conduct an aerial survey. Ten swans were observed at the Summer Lake Wildlife Management Area, all of which were translocated from Malheur NWR (6 cygnets) and Wyoming Wetlands Society (4 yearlings). The count for Nevada was about the same as in recent years. Precipitation throughout most of the tri-state area was average during winter 2008-2009. During the summer months, temperatures were slightly below average and precipitation was above average. Palmer Drought Indices for areas within the tri-state region ere improved from values during summer 2008.
Comments
U. S. government work.