[obol] historic Whistling Swan numbers
- From: Lars Per Norgren <larspernorgren@xxxxxxxxx>
- To: obol@xxxxxxxxxxxxx
- Date: Sat, 21 Feb 2015 15:25:32 -0800
The US Fish and Wildlife Service conducts aerial waterfowl surveys that
probably give quite accurate numbers for swans in the Willamette Valley in the
early seventies. I tend to assume the current population is double or triple
what it was then.
This could be due to continued growth of that original cohort, or it could be
due to recruitment from other wintering populations. Small numbers of Whistling
Swans began to appear on the Oregon Coast in winter in the late 60s and
gradually grew. The species was regular on the Coos Bay CBC back then, followed
by a long hiatus. I wonder what the continental trend is. Lars
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