Subject: [Tweeters] Re: more about bunting ID
Date: Jan 19 19:03:45 2005
From: Jason Rogers - hawkowl at hotmail.com


Thanks to Dennis for going through Pyle and relaying its information to
myself and the rest of the group.

I'd first like to make some comments on Pyle. This volume, as I'm sure many
are aware, is a standard reference for banders. Thus much of the
identification criteria it provides for each species is useful only when the
object of an identification is nestled between one's index and middle
fingers.
It is perhaps for this reason that the reference is not comprehensive in its
presentation of aging and sexing criteria. For example there appears to be
no discussion of scapular feather patterns in the two bunting species.
Other information provided is too general to be of any use (e.g., Snow
having less white in the wings and tail than McKay's). Furthermore Pyle's
mention of adult male McKay's usually having mantle feathers with small
black centers may be erroneous. I would strongly urge anyone interested in
identifying either the Iona bird or Harrison Hot Springs bird to consult the
North American sparrow guides. Pyle doesn't appear to have enough of the
kind of information necessary to make these identifications.

In regards to the effect of wear on feathers, I've taken this into account
when making my identifications of the buntings. Black areas of feathers are
more resistant to wear than white ones. Thus even though the buntings are
in relatively fresh plumage, they should be reliably sexed on the basis of
the shape of the dark centers of their scapulars.

I'm not sure that the absence of some rectrices in each of the two Iona
McKay's Buntings during the early part of December would be of any use to us
for identification purposes. These birds, if adults, should have completed
their prebasic molt by September. I noticed that the male lost his R1 pair
soon after his arrival, and the female was growing in at least two of her
left outer rects around the same time. Furthermore these rects lacked the
amount of pigment that the corresponding ones on her right side showed. A
couple of theories have been put forth to explain this. It is thought that
the birds might have left the breeding grounds prior to having completed
their molt. If so, the molt might have been suspended until the birds
reached their destination. Stressed by her journey, the female may have
been unable to supply her developing rects with a normal amount of pigment.
The other theory suggests that the birds lost rects during encounters with
predators. I think this is the more likely one, since rects are molted in a
sequence that, at least in the male, was not being followed. Certainly the
birds were much whiter and, thus, more conspicuous than the Snow Buntings
they were with. This may be why there have been no recent sightings of the
male.

I don't know if Bethel, AK has a Christmas Bird Count, but if it does, it
would be interesting to see if the folks there picked up any McKay's last
Christmas.

Regards,
Jason Rogers
Banff, AB
hawkowl at hotmail.com