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Another Swainson's Warbler



HI . . .

You may recollect my May Day 2000 announcement that I had just 
captured my first-ever Swainson's Warbler (Limnothlypis swainsonii) 
at Hilton Pond Center for Piedmont Natural History near York, South 
Carolina.

This bird was also mentioned on the Carolina Rare Bird Alert because 
it breeds in the Coastal Plain and the mountains but is seldom seen 
in the Piedmont, even during migration. The May Day bird is pictured 
on the Hilton Pond website at 
http://www.hiltonpond.org/ThisWeek000501.html .

I'm pleased to relate that this morning (30 May) I caught my second 
Swainson's Warbler at Hilton Pond. This is a rather late date for a 
spring migrant.

When I examined the bird closely, I discovered it might not be a 
migrant after all because it was a male in breeding condition, as 
determined by a well-developed "cloacal protuberance." (In case 
you're not familiar with the structure, it is a swelling around the 
cloacal area caused by temporary storage of sperm in the vas 
deferens. Only present during the breeding season, it allows the male 
bird's sperm to be stored "outside" the body  cavity, where the 
bird's high body temperature would actually kill the sperm. Having 
sperm stored this close to the cloacal opening also allows for quick 
sperm transfer during copulation, AKA the "cloacal kiss.")

All this is exciting news, especially if it indicates what would be a 
significant breeding range expansion for the uncommon Swainson's 
Warbler.


Best wishes,

BILL
-- 
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BILL HILTON JR., "The Piedmont Naturalist"
Hilton Pond Center for Piedmont Natural History
1432 DeVinney Road
York, South Carolina 29745
USA

e-mail: <hilton@hiltonpond.org>

Voice: (803) 684-5852

eFax: (503) 218-0845

Hilton Pond Center for Piedmont Natural History is a 501(c)(3) 
non-profit research and education organization, so all in-kind or 
monetary gifts to Operation RubyThroat and the Center are 
tax-deductible. Please visit our websites:

Hilton Pond:  <http://www.hiltonpond.org>

Operation RubyThroat:  <http://www.rubythroat.org>


"Never trust a person too lazy to get up for sunrise or too busy to 
watch the sunset."

						BHjr.

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