>See the New York Times (the only REAL newspaper available to
>Northwest residents), January 3, for an extensive article on the
>multiple subspecies of red crossbills. A graphic display shows how
>birds sounds differ by bill type no matter where they were recorded.
>Interesting discussion on whether diversity is required by seed
>types. But if that is true then why are different bill types found
>in the same areas? Do different bill types mix in common flocks?

Although I don't regularly see it, I know the New York Times is a wonderful
newspaper, and the articles on biology that I do see are usually
well-written and authoritative.

Did they say "subspecies," Barbara? They should have said "species," as
that's what the work of Jeff Groth, Tom Hahn, and Craig Benkman has shown.
There are 8 species of Red Crossbills in North America, as indicated by
flight calls and size and bill-size differences. The bill-size differences
relate to preference for different conifer seeds. The critical thing is
that these are *preferences,* not absolute differences. Many species feed
on a wide variety of conifers, so in a Douglas-fir tree on the east side of
the Cascades you might hear type 4 birds, the Douglas-fir "specialist," but
also type 3, the hemlock/spruce "specialist," and type 2, the ponderosa
pine "specialist." In each case you typically find large numbers of the
appropriate type in the appropriate forest (when they are bearing cones, at
least), but there is slop. Tom Hahn and I tape-recorded FOUR types in one
area on Whidbey Island last year.

The different flight-call types do mix, even in flocks (as do many species
in other groups of birds, in this family for example, siskins, goldfinches,
and redpolls), but perhaps not all that much; they have somewhat different
agendas. Typically if you played a tape of a type 2 bird at that
theoretical Douglas-fir tree, the type 2 birds would come down to check it
out but the others wouldn't. They have hybridized in aviaries, but no one
knows whether or how often they do so in nature. But so many bird species
have hybridized in nature, this is not evidence against their specific
status.

What is awesome about this in Tweeterarea (surely as good a name as
Cascadia?) is that we probably have 6 of the 8 species; this has led to a
lot of *arrggghhs* in past discussions, as you might guess. Three of the
types (2,3,4) are common and widespread, two (1,5) are more restricted, and
one (7) is scarcely known in the area (not yet from Washington). See
WOSNEWS #27 for more information.

Dennis Paulson 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