Subject: vagrancy
Date: Dec 13 16:53:34 1995
From: Dennis Paulson - dpaulson at ups.edu
Having followed both Don's and Al's arguments, I wonder if we're using the
right word.
"Vagrants" by the usual definition in birding circles are well outside
their normal range (e.g., this longspur apparently wintering a great
distance from its normal range, both latitudinally and longitudinally,
although a few have been found in winter in eastern CA), and I suspect such
birds by and large won't have much to do with the changes in bird ranges
that probably happen continually and ultimately cope with long-term
changes.
I spent a lot of time once trying to find examples of birds that colonized
disjunct areas on the basis of what might have been vagrants--at least
birds well away from the normal range. They are extremely few and far
between, even though, yes, there are some. And these distant colonists
for the most part wouldn't be significant in the scheme of gradual (or
quicker) climatic changes. This is probably most likely to happen on
islands distant from the mainland when an entire flock of birds strays and,
for some reason, fails to leave (maybe they haven't a clue on how to get
home, probably much like our longspur!).
Whether the normal slow flux of bird ranges can deal with phenomena such as
global warming will be interesting to see. Birds should be able to
certainly handle it a lot better than salamanders, for example.
Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416