Burt Guttman wrote:

"Question 2: This is where Dennis and I have disagreed. He takes a
strong adaptationist viewpoint; he points out that to produce a certain
structure or engage in a certain behavior takes energy, so there must
always be a reason why that structure or behavior is there. He makes a
good point, and I'm not taking a strong anti-adaptationist stance. But I
have read Gould and Lewontin's paper "The Spandrels of San Marco and the
Panglossian Paradigm," and they make a good case for not assuming that
everything an animal does is an adaptation for some purpose. Krebs and
Davies have made the point by saying that when flamingoes stand against a
pink sunset they're well camouflaged, but we certainly don't think their
pink color is an adaptation for this purpose.

I guess the only take-home lesson I can suggest for now is that we
shouldn't naively look at a bird (or any animal) doing something that
strikes us as odd and assume there's some kind of adaptational reason for
it. Some actions may be inconsequential byproducts with no function at all."

Since my name has been taken (I don't know where they got that phrase "in
vain," however), I feel the need to reply.

If I didn't have an adaptationist viewpoint, I doubt if I would watch birds
much, or have as much fun going out in nature. I *have* to think that what
I see in nature has "meaning," and I'm speaking strictly in adaptationist
terms when I say that. If I couldn't look at a flamingo and feel that
there was some evolutionary explanation for its being pink, it would take a
lot of joy out of my particular viewing of nature. Not all of it--as I can
enjoy a flamingo in other ways too--but a sizable chunk of it. Personal
viewpoint, obviously, but it certainly colors my approach to science.
Gould and Lewontin perhaps get a different kind of kick from viewing nature
(they live in Boston, after all).

And, speaking of flamingos, large flocking birds tend to be colored to
contrast with their environment so they can easily locate one another, and,
if you've seen a flock of Greater Flamingos against the water and mangroves
and sand of a tropical lagoon, you need look no further for an
adaptationist argument. Their crustacean diet, rich in carotenoids, allows
them easily to produce pink feathers, whereas egrets, for example, might
not be able to do so and thus have to get by with white (which is probably
equally conspicuous in the same environment).

As for my test, I'll see Krebs and Davies and raise them one prediction. I
predict that flamingos don't do a lot of their looking for flockmates at
sunset!

Thanks for sending me some old business, Serge. I don't know diddly-squat
about why gannets stretch their neck before taking off, but I feel very
comfortable with the "signaling the group" hypothesis. And just because
members of one or more other species of bird *don't* stretch their necks
when taking off from a colony in no way invalidates the hypothesis for
gannets, which after all tend to be *very close* neighbors. I agree fully
that any hypothesis needs testing to gain validity and that one of our most
common errors is to confuse hypotheses with conclusions.

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