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From: dmark@acsu.Buffalo.EDU (David Mark)
Newsgroups: rec.birds
Subject: Re: MacGillivray's Warbler variant song query
Message-ID: <29421@eerie.acsu.Buffalo.EDU>
Date: 27 Jun 90 12:15:57 GMT
References: <29148@eerie.acsu.Buffalo.EDU> <306@spam.ua.oz> <151@sun13.scri.fsu.edu>
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In article <151@sun13.scri.fsu.edu> sandee@sun13.scri.fsu.edu (Daan Sandee) writes:
>In article <306@spam.ua.oz> wvenable@spam.ua.oz (Bill Venables) writes:
>
>[ story about wedgebills being distinguishable by voice only ]
>
>>More recently the two have been re-classified and are now regarded as
>>conspecific, although such are the vagaries of academic pigeon-holing
>>I can't say for how long. :-)
>>Regards,	Bill Venables.
>
>Interesting. The A.O.U. (that's American, not Australian) treats two
>populations as distinct species if they, under normal circumstances,
>do not significantly interbreed. Whether they are sympatric or allopatric
>is not really an issue, although it makes the determination of the degree of
>interbreeding much easier if they are allopatric. 

I don't think the A.O.U. is acting this way.  It is the *sympatric* species
that are easier, since they can be observed in the field, and their
interbreeding, or non-interbreeding, can be observed directly (usually).
But allopatric species (which cannot by definition interbreed in the wild
because they do not come in contact in the breeding season) are lumped
or split, based on whether it is believed that they would interbreed if they
came into contact in the wild.  And if the interbreeding would lead to
blending, establishing a cline with a hybrid zone containing no parental
phenotypes.

So, the Florida and Western populations of "Scrub Jay" are considered to be
subspecies.  European and American populations of Long-eared Owl.  Etc.

>                                                   From your description,
>it sounds as if the wedgebills should be regarded as two species.
>In the U.S., the only recent case of a voice-based split is the Traill's
>Flycatcher, which was split into Alder and Willow Flycatcher. The two
>species have a largely similar distribution, but within that area prefer
>different habitats. They can (apart from choice of habitat) be distinguished
>by song only - well, sort of ; actually, the songs aren't all that different.
>

Recently, the American O.U. has been using voice as a more important criteria
for allopatric yet morphologically very similar forms.  Thus, our Brown
Creeper is now Certhia americanus, having been split from the European
species because whereas it is morphologically very similar to Tree Creeper
(C. familiaris), the voice of americanus is very similar to the Short-toed
Creeper of Europe.  The fact that "they" have not lumped Marsh Tit with
Black-capped Chickadee is based on distinct voice.  The spit of Western 
Flycatcher (Empidonax diffficilus) into Cordilleran and Pacific-slope
Flycathcers (**TERRIBLE** English names, by the way!!) was largely voice-
based.

>I can think of no example in American ornithology where two species that
>were distinguishable by voice only, have been lumped.
>
And, the cynic sez:  There haven't been any voice-based lumps yet, only because
                     voice-only-based splits are so new.  Just give them time!!


>Daan Sandee                                           sandee@sun16.scri.fsu.edu
>Supercomputer Computations Research Institute
>Florida State University, Tallahassee, FL 32306-4052  (904) 644-7045

David Mark
dmark@acsu.buffalo.edu