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 484 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2010, 2.3% higher than the count from last year (473). The number of white birds in the tri-state region (375) increased for the first time in three years and was near the recent high count in 2007 (383). The total number of cygnets increased from 75 in 2009 to 107 in 2010. Cygnet counts increased from 2009 by 3.8% and 45.5% for Idaho and Wyoming respectively, while Montana cygnet production decreased by 4.3%. Malheur National Wildlife Refuge (NWR) accounted for only 2 swans this year but once again, the survey was incomplete. Eleven swans were observed at the Summer Lake Wildlife Management Area, all of which were translocated from areas in Wyoming. As of the date of this report, Nevada did not supply data for 2010. Precipitation throughout most of the tri-state area was well below average during winter 2009 - 2010. 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 were improved from values during summer 2009.