[Tweeters] RE: What happens to 'lost' birds?

Mike Patterson celata at pacifier.com
Thu Sep 29 19:32:56 PDT 2005


RE: What happens to 'lost' birds?

My father used to say, when we were in the middle of nowhere.
"We're not lost, we're just a bit confused". Lost is a matter of
definition.

Those hoping for definitive data based on banding studies are
likely to be disappointed. The probability of recapturing any
migrant in a different spot is astonishingly low. I've been
banding for 20 years or so and have never caught anybody else's
birds and have only had two of mine recovered (both dead). I
recapture birds I've banded routinely. however, rates for Song
Sparrows and chickadees run at about 12% and rates for Swainson's
Thrushes run about 8%.

It's hard to say whether out of place birds get back to their
point of origin. Survival rates among most bird species run at
about 80% mortality in the first year. A vagrant bird is most
probably part of a much larger statistical group of individuals
lost from the gene pool. Even if a bird survives in an out of
range spot, if it fails to find a mate, it remains permanently
lost in the genetic sense. There are plenty of vagrancy success
stories, though, from Cattle Egrets to Darwin's Finches.

There are probably one or two specific data points out there that
tell the story of a vagrant or two banded and recovered. RUFOUS,
ALLEN'S and CALLIOPE HUMMINGBIRDS have been recaptured in multiple
years in Louisiana and Alabama. These records definitely speak to
winter site fidelity, but it's hard to say whether they represent
geniune vagrant success stories or something else since there is
data from the other end of their migrant cycle.

I can only offer anecdotal testimony on other species. A NORTHERN
MOCKINGBIRD seems to have returned to the same holly bush three
winters running in Hammond. It was unbanded so it might have been
three different mockingbirds finding the same holly tree in three
consecutive years....

The same neighborhood in Seaside always seems to get 2 or 3
TROPICAL KINGBIRDS every year, usually an adult and a couple
hatch-years. Again, no bands, just circumstance.

In 2003, a 1st-winter male BULLOCK'S ORIOLE spent the winter at a
suet feeder a couple blocks from my house. Last winter a 2nd-
winter male BULLOCK'S ORIOLE spent the winter at the same feeder.

--
Mike Patterson
Astoria, OR
celata at pacifier.com

And now for something completely different... Salamanders
http://www.surfbirds.com/blogs/mbalame/archives/002899.html



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