US Fish & Wildlife Service


Date of this Version



U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.


U. S. government work.


Observers counted 459 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2008, 13% lower than the count from last year (527). The number of white birds in the tri-state region (379) was about the same as in 2007 (383), but the number of cygnets declined 58% and was the lowest since 1993. Biologists attributed the decline to cold and snowy weather conditions, which are not conducive to successful reproduction. The numbers of young produced in Montana, Idaho, and Wyoming were 83%, 67%, and 39% lower, respectively, than those of last year. The abundance of total swans at Malheur National Wildlife Refuge (NWR) was the essentially the same as the 2007 count, which was the lowest recorded since 1967. No swans were observed at the Summer Lake Wildlife Management Area and vicinity this fall for the second consecutive year. The count for Nevada was about the same as in recent years. Precipitation throughout most of the tri-state area was average or below during winter 2007-2008. During the summer months, temperatures were slightly above average and precipitation was below average. Palmer Drought Indices for areas within the tri-state region were only slightly improved from values during summer 2007.