The question of species concepts came up in a recent post from Glen Ingram
about Coxen's Fig Parrot. This is something I have been fretting over
greatly in recent months. As a guide to most decisions about bird species,
the Biological Species category is hopeless. As a CONCEPT, it is quite
clear. But as a CATEGORY, it invites taxonomists to use inference in
answering most questions, and this is about as arbitrary or unscientific as
you can get. Obviously if we take the definition of species in the
Phylogenetic Species concept literally, every breed of dog would be a
species, and this is crazy. DNA sequencing will presumably put us all out
of our misery; eg if the genetic difference is 2% or more, we're dealing
with 2 species. But in the meantime, I think it's bizarre to say that the
American and African Comb Ducks are one species, when they are different and
have been separated for a hell of a long time. Another bee in my bonnet,
which I have raised in various contexts is the Cinnamon Quail-thrush
complex. If you split out Chestnut-breasted castaneothorax in S.Queensland,
with Cinnamon in between (why was Nullarbor Q-t, alisteri, lumped with
cinnamomeum? Is there any evidence of interbreeding?) how can you say the
form in Western Australia is also castaneothorax??? If we are talking
gene-flow here,as opposed to inference, you must split the WA form off as a
good species too!
In the case of birds, I am inclined to say that if we have sympatric or
parapatric forms with no or minimal interbreeding, or diagnosably different
allopatric forms, these should all be treated as species. This will
probably double the number of species, and be a nuisance to birdwatchers,
but entomologists are quite comfortable with such criteria. Also, not every
race will become a species. A lot of morphometric races will be lumped,
since the measurements of one form often overlap those of another form.And
genuine interbreeding should be taken as evidence of conspecificity. And
yes I am aware of wierd cases like that found by Sibley in Mexico for some
passerine where some populations were sympatric and didn't interbreed, while
others were sympatric and did interbreed. Since we are imposing boundaries
on a continuum, there will be hard, boundary-spanning cases whatever
criteria you assume. But I've had enough of inferential bullshit.
John Penhallurick
Associate Professor John M. Penhallurick<>
Canberra, Australia
Phone BH( 61 6) 201 2346 AH (61 6 2585428)
FAX (61 6) 258 0426
Snail Mail Faculty of Communication
University of Canberra, PO Box 1, BELCONNEN, A.C.T.2616,
AUSTRALIA
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"I'd rather be birding!"
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