Date of this Version
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Observers counted 4,701 swans (white birds and cygnets) in the Rocky Mountain Population of trumpeter swans during January and February 2007, a decrease of 14% from the 5,484 counted during winter 2006. However, in Montana, aerial surveys were conducted only in a portion of the survey area; ground counts were conducted on remaining areas. The numbers of white birds (3,660) and cygnets (919) decreased 14% and 25%, respectively, from counts last year, although these declines are biased high due to a number of birds in Idaho not being classified as either white birds or cygnets. In the tri-state area, decreases in total swans occurred in Montana (-44%) and Idaho (-14%), but increased (+14%) to a record-high count for the third consecutive year in Wyoming. The number of birds wintering in areas near restoration flocks was the highest since 2001, due largely to a 67% increase in the number of swans counted at the Summer Lake Wildlife Management Area. A record low number of swans was counted at Malheur National Wildlife Refuge, while the number of birds at Ruby Lake NWR increased slightly. Reservoir levels in early February increased 11% from levels during 2006, and were 8% above the long-term average. Generally, temperatures in the tri-state area during winter 2006-07 were average or slightly warmer than average, and precipitation was below average.