Date of this Version
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Observers counted 5,368 swans (white birds and cygnets) in the Rocky Mountain Population of trumpeter swans during February 2014, which was a 16% decrease from the 6,425 counted during winter 2013. However, the long term trend from counts for total swans of the RMP suggested an increase (P<0.05) of 5.4% per year during 1972 – 2013. In the tri-state area, the number of total swans decreased for Montana (-17%), Idaho (-19%) and Wyoming (-10%) from counts in 2013. Weather may have contributed to the decrease in numbers. Weekly snow storms came through the area for the entire month of February making coordinated aerial surveys difficult. Despite the decrease in total swans from 2013, the long term trend from counts for total swans for Montana, Idaho, and Wyoming is increasing. The number of birds wintering in areas near restoration flocks increased by 38% from last winter. The numbers of birds at Ruby Lake National Wildlife Refuge (NWR) (32) decreased by 14% while the birds at Summer Lake Wildlife Management Area (WMA) (141) increased 66% from 2013. There was no survey at Malheur NWR in Oregon for this year. Reservoir levels in early February were lower than during winter 2013 and 35% below the long term average. Temperatures in the tri-state area and in Yellowstone National Park during winter 2013-14 were below the long term average.