Breeding distribution and abundance of trumpeter swans (Cygnus buccinators) in British Columbia, summer 2005 / André Breault, Bruce Harrison, Steve Shisko. : CW69-5/475E-PDF

"This report presents the results of the Trumpeter Swan (Cygnus buccinator) breeding survey conducted in British Columbia in 2005 and a summary of similar surveys conducted since 1985. Aerial (fixed-wing) surveys were conducted over the known breeding range of Trumpeter Swans in the province in mid-August 2005, to coincide with the brood-rearing period of flightless young. The population of Trumpeter Swans breeding in British Columbia was estimated at 1,126 birds (808 adults and 318 cygnets) in 2005, the highest recorded since 1985. Brood size averaged 2.66 young per brood. The Rocky Mountain population (905 birds in 2005) remains larger than the Pacific Coast population (221 birds in 2005). The breeding population of Trumpeter Swans in British Columbia has grown at an estimated (arithmetic) rate of annual increase (r) of 10.7% between 1985 and 2005. Range extension into previously unoccupied breeding areas accounts for much of this growth"--Abstract, p. i.

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