Tony,
I suspect the harsh response from Chris was driven by the tone of some emails
that stated that because the two forms of Sooty Owl are field diagnosable than
they were clearly good species and ergo C&B and the taxonomists are wrong.
Apperance is one element that can help you determine whether a group of birds
is a species or not, but there are plenty of birds that look different that are
in fact the same species responding to different ecological factors in a
particular part of the range with very little 'real' difference beyond how they
look. Given enough time they might be sufficiently differentiated to be called
species. In a few million years you might get your wish and the Sooty Owl
populations are formally split. Alternatively the ecological circumstances that
might drive current variation between the appearance of the populations might
level out and there will be less difference. Who knows.
At the same time there are plenty of examples of good species that are very
difficult to diagnose in the field. There is an interesting case with
logrunners uncovered some years back (and people keep uncovering new crossbill
species!) where birds the birds in New Guniea and Australia are
indistinguishable in the field but diverged millions of years ago and are
genetically very different.
At the end of the day, you can of course keep your field notes and lists
however you like. Species limits and individual diagnoses are always open to
debate and revision in closely related populations.
But I would caution against reducing the science to 'it looks different so it
must be another species'....
mjh
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