[Birdtalk] From David Wheeler on Glossy Ibis

[Mark Stackhouse]

David asked that  post the following musings:

Hello, fellow birders.

I just have a couple of rambling thoughts and a
request regarding the Glossy ibis sightings many of
you are likely about to make.

It is interesting that a bird with no previous
reported sightings in Utah might, if the current trend
in birder success stories continues, go directly from
the status of "hypothetical" to "rare" or even
"uncommon".  It is a wonderful case illustrating how
we do not see what we don't imagine to look for.

I encourage everyone who feels comfortable with their
identification of a Glossy ibis in Utah to submit
their  reports to the Utah Ornithological Society
Records Committee for review.  I realize the Glossies
probably aren't yet even officially listed as a
"review species", but the more records we have, the
better understanding we'll have of the status and
distribution of that species in Utah.  Think of it as
contributing to science.

Occurences of hybrids would be interesting to document
as well.

Toward that end, it might also be helpful, in an
informal way, to know how many times people go out and
search flocks of ibis but fail to find Glossies, so
our community data isn't skewed toward the positive.
I realize that many of us don't like to report
"failures" but in this case a lack of Glossy
encounters is useful data as well rather than a
"failure".  I therefore encourage those of you out
there who feel you know how to differentiate the two
species to let us know on Birdtalk how you fare.
[And, Milt, if this becomes an unmanageable flood of
e-mails clogging the system, please jump in to let us
know that my idea is unworkable and pernitious!!]

=>People who dislike taxonomic issues should stop
reading right now or proceed with caution and
knowledge of having been forewarned.

My other musing, which I especially throw out to the
Records Committee members, is that I wonder whether a
pair of species (presumably a superspecies) which
hybridizes to such a great extent (as seems to be
indicated by Cliff in Idaho and the folks in Cache
Valley) is truly a pair of species or just
long-separated subspecies (i.e. kissing cousins).  I
wonder, therefore, whether the two species of Plegadis
ibis might better be treated as conspecific and are
heading for a lump.  Does anyone know how broad their
zone of hybridization is?  Or is the shockwave of
Glossies too new for studies to have been published?
It would be ironic if the Glossy ibis, so new to our
Utah experience and lists, was in fact, in a sense, a
transient phenomenon.  [Though, in actuality, the
Glossy ibis, being from the Old World, is likely to
have been described first in science, so would
probably take precedence if the two were lumped.  In
other words, rather than gaining an extra ibis, we
might just someday have to replace "White-faced ibis"
with "Glossy ibis" on all of our lists.]

OK, I had to go and check the literature (AOU
Checklist, 7th ed, 1998):
#1 - yes, the two constitute a superspecies
#2 - yes, the Glossy was named in 1766 and the W-F in
1817, so the Glossy was named first.
#3 - The two species were formerly considered
conspecific but sympatric breeding occurs on Avery
Island, Louisiana, (i.e. their breeding ranges overlap
on a small bit of land where they were presumably
deemed to prefer their own kind when given the
opportunity, suggesting to researchers that they were
"true" separate species).

So there you have it.  Nature is a wondrous continuum
of variety, and cares not where we draw the lines.
However, those who care what the "official"
taxonomists say about what is countable, stay tuned to
what the AOU eventually decides (probably decades from
now...).
[of course, those of you who "keep your own lists"
irrespective of official sanction, you need not
trouble your sleep tonight and can smugly smile in
your pillows at those of us who fret]

Happy birding, Junior Scientist!

David Wheeler


Mark Stackhouse
mark at westwings.com
801-487-9453 (Salt Lake City, Utah, USA)
011-52-323-285-1243 (San Blas, Nayarit, Mexico)