Wow, this is really great stuff, worthy of a bulletin board,
although--oops--as Don pointed out, it's not about birds any more. I'll do
my best to get us back on the avian track.

All the contributors' points are all well taken. We probably goofed using
the term "indicator" species. We should merely be thinking about the
effects global climatic change would have on birds of different kinds, and,
while doing so, try to predict some changes in their occurrence and/or
abundance in a given area, realizing at the same time that there are many
possible causes for such changes. But that's what science is, trying to
distinguish among alternative hypotheses.

Absolutely, resident species should be more amenable to monitoring than
migratory ones, as range changes couldn't merely represent oversprings or
shortfalls. On the other hand, I would say that birds are among the best
animals to monitor, for the usual reasons of their being diurnal, large,
conspicuous, and vocal (not to mention appealing to scientists and
nonscientists alike), and I imagine they would respond more quickly, in
larger jumps, to climatic changes than plants and most less vagile animals.

Probably a much more interesting question about shorebirds is why some
species RIGHT NOW have different limits to their winter ranges. We know
essentially nothing about this in North America. Why are Dunlins so
abundant here in winter, yet Western Sandpipers and Short-billed
Dowitchers, which share that abundance in migration, aren't?

Why do Dunlins winter farther north than the others? Why do Black-bellied
Plovers winter here and Semipalmateds not? Why Rock Sandpipers but not
Wandering Tattlers? Why Killdeers but not golden-plovers? Why not large
shorebirds, for the most part, when they are so abundant in California? If
it was merely the lack of large prey up here, then I would predict
Semipalmated would winter but not Black-bellied.

Do Dunlins winter farther north because they can complete their autumn molt
in Alaska or do they complete their molt in Alaska because they winter
farther north? I could see that they might be successful at eating prey
that would otherwise have been available to Western Sandpipers, but
dowitcher prey I assume would be deeper in the mud. Or are the prey
species that dowitchers eat much less common in winter? Plenty of
questions, at least some of which probably could be answered by studies on
the species and their prey. Answers to simple questions of this sort would
go a long way to generating hypotheses of what MIGHT happen with global
warming, cooling, or anything else.

And these are only shorebird questions. The same could be asked of other
taxonomic groups, although I feel we understand many of the other groups
(hawks, owls, waterfowl, passerines, for example) a lot better.

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