[texbirds] Re: GHOW subarctic race?
- From: Mitch@xxxxxxxxxxxxxxxx
- To: tripp.davenport@xxxxxxxxx
- Date: Tue, 06 Nov 2012 08:56:35 -0600
Hi Tripp, and all,
I post this publicly not to pick on Tripp, but since this
is not the first time this exact thing has happened, a wider
audience might benefit.... Tripp is not the first nor will
be the last to fall into the Nat. Geo. subspecies trap.
For many species there are a large number of subspecies.
Some field guides, like Nat. Geo. in particular, name or
show a few variations. In some cases there are a few or
even a half-dozen shown, when there are 5, 10, 20, or more
subspecies (by 5th AOU definitions, I think the last time AOU
addressed subspecies, in the last millenium, 1955).
It is not uncommon for the fact that not all subspecies are
shown to be lost by users, though I think mentioned in the
introduction. Many work from the belief that what is shown
are all the choices.
Generally the subspecies shown are to show the range of
plumage variation, not all the subspecies. For instance
with Great Horned Owl there are pale southwestern desert types
that look about as pale as illustrated subarcticus, and which
are not mentioned. This is the typical situation in Nat. Geo.
with regard to species with multiple subspecies.
So, voila, when a pale southwestern desert (c.f. B.v. pallescens -
Western Great Horned Owl) type is seen, it is suggested to
be the closest match in the book, subarcticus. Since it
clearly is so much paler than the nominate eastern types
generally depicted in most guides. Nat. Geo. could have labelled
the illustration pallescens and it would be close enough for
many pallid individuals of that particular subspecies.
Especially the desert individuals.
This sort of sub-specific ID error is how we know one is
using the Nat. Geo. Guide, the greatest source of incorrect
sub-specific identifications in modern birding. :) The
illustration of subarcticus is to show the pale end of
GHO plumage, not to identify the subspecies with. :)
The Crossley ID Guide shows a bird that looks quite like
Nat. Geo.'s subarcticus, labelled 'southwestern' which is
surely a pallescens type. I see these at Uvalde, they are
the ones in the brush country habitat. Though Oberholser in
Bird Life of Texas draws the easternmost pallescens (as resident/
breeder) line along the eastern edge of the Balcones Escarpment,
it seems to me the ones up here in the hills are much darker brown
and more rufous, whereas the ones in the cenizo and brush
country, or deserts to the west, are often these paler grayer
types.
Mitch Heindel
Utopia
www.utopianature.com
Quoting Tripp Davenport <tripp.davenport@xxxxxxxxx>:
> Took some photos of a white great horned owl with tufted horns today
> at Lake Balmorhea in West Texas (Reeves county). I am not familar
> with the subarctic race of GHOW and was wondering if anyone else
> might know something about it? The pics are posted on my flickr
> page...
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