TRUMPETER SWAN SURVEYof theROCKY MOUNTAIN POPULATION,U.S. BREEDING SEGMENTFALL 2009

Observers counted 606 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2013, a 2.2% increase from last year’s count (593). The number of white birds in the Tri-state region (451) increased 18% from last year’s count of 381. The total number of cygnets decreased 38.2%, from 178 in 2012 to 110 in 2013. Cygnet counts decreased from 2012 by 72.9% and 6.7% for Montana and Idaho, respectively, while Wyoming cygnet production remained the same as last year at 52. Malheur National Wildlife Refuge (NWR) did not conduct the swan survey this year. Twenty-four white birds were observed at the Summer Lake Wildlife Management Area, which was an increase of 41.2% from last year. Nevada counted 20 swans on this year’s survey. Precipitation throughout most of the Tri-state Area was 65% – 85% of normal during winter 2012 2013. During the summer months, temperatures were 1 – 3 F warmer than average and precipitation was 25 – 50% of normal, especially during June August. Palmer Drought Indices for areas within the Tri-state region declined for the second year for 2013. The Rocky Mountain Population (RMP) of trumpeter swans (Cygnus buccinator) consists of birds that nest primarily from western Canada southward to Nevada and Wyoming (Fig. 1). The population is comprised of several flocks that nest in different portions of the overall range. The RMP/Canadian Flocks consist of birds that summer primarily in southeastern Yukon Territory, southwestern Northwest Territories, northeastern British Columbia, Alberta, and western Saskatchewan. The Tri-state Area Flocks summer in areas at the juncture of the boundaries of Montana, Wyoming, and Idaho (hereafter termed the tri-state area) and nearby areas (Fig. 2). The RMP/Canadian and Tri-state Area flocks winter sympatrically primarily in the Tri-state area. In addition, efforts have been made to establish several restoration flocks, such as those at Ruby Lake NWR in Nevada (i.e., Nevada flock) and those at Malheur NWR and Summer Lake Wildlife Management Area (WMA) and vicinity (i.e., Oregon flock), by translocating adult swans and cygnets from other portions of the RMP. These birds tend to winter in areas near those where they nest. This report contains information only from the Tri-state Area and restoration flocks, collectively referred to as the RMP/U.S. Breeding Segment. These terms for the various groups of swans are consistent with the Pacific Flyway Management Plan for the RMP of Trumpeter Swans (Subcommittee on the Rocky Mountain Population of Trumpeter Swans 2008). The Fall Trumpeter Swan Survey is conducted annually in September. The survey is conducted cooperatively by several administrative entities and is intended to provide an accurate count of the number of RMP trumpeter swans that summer in the U.S. The history of the survey dates back to the 1930s, although methods and survey coverage have changed over time as the number of swans increased and new technologies became available. To be consistent with previous reports, only data from 1967 to present were analyzed for this report. The data are used by managers to assess the annual status of the Tri-state Area Flocks and restoration flocks.

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