TRUMPETER SWAN SURVEY of the ROCKY MOUNTAIN POPULATION, U.S. BREEDING SEGMENT FALL 2003
Observers counted 417 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2003, an increase from 371 counted from comparable areas last year. The increase was attributable mostly to an increase in production (+60%) from that...
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| Format: | Text |
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DigitalCommons@University of Nebraska - Lincoln
2003
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| Online Access: | https://digitalcommons.unl.edu/usfwspubs/505 https://digitalcommons.unl.edu/context/usfwspubs/article/1493/viewcontent/survey_fall2003.pdf |
| Summary: | Observers counted 417 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2003, an increase from 371 counted from comparable areas last year. The increase was attributable mostly to an increase in production (+60%) from that in 2002; the number of white birds (321) was slightly higher than that of last year (311). Increases occurred in all 3 states in which the Tri-state Area Flocks nest, and was greatest in Montana (+26%). Increases in Idaho and Wyoming were 9% and 23%, respectively. The number of birds in restoration flocks (Malheur and Ruby Lake National Wildlife Refuges only) decreased 31% compared to the count from last year, and the count for Malheur was the lowest since 1967. For the third consecutive year, swans at Ruby Lake produced no young. The tri-state area continues to experience severe drought conditions, with Palmer Drought Index values during early fall of 2003 the lowest recorded since swan surveys were initiated in the 1930s. |
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