[CT Birds] Interior Nelson's

charles barnard jr chbarnjr at gmail.com
Fri Oct 21 17:38:39 EDT 2011


Paul,

I have exchanged emails with Chris Elphick on the subject of identifying
Nelson's Sparrow by races. Chris  has been generous enough to send me photos
of labeled museum specimens and offered me his thoughts on the subject.  I
agree with Chris that the Nelson's Sparrow subspecies change appearance
gradually across a cline and that there are many birds which are not clean
"textbook" examples of a particular subspecies. Hybridization
between Nelson's and Saltmarsh Sparrows also occurs, which complicates the
matter further.

However, I also feel that Nelson's Sparrows which are at either end of the
wide spectrum can be definitely identified as to exact subspecies. The
noticeably  large, extensively soft gray Acadian birds with blurry
gray  streaking on the flanks (the gray on the flanks matches the shade of
gray on the back) are distinctive. Way over to the other end end of
the spectrum is the nominate nelsoni, found in prairie wetlands.  I  have
seen only 1 of these in Connecticut and it was just as Sibley depicts it -
with a gleaming face and chest, small bill, small overall size and with
red/maroon colored streaking on the flanks.  It looks nothing at all like
the Atlantic/Acadian race.

The James Bay race, alterus, is the problem maker. This bird is not usually
even depicted in field guides and probably for good reason, since it can
apparently be quite variable in appearance. To me, it often resembles a
Saltmarsh Sparrow, just to make things more difficult. As a template to
assist me in being able to pick out an alterus, I often refer to the only
photo which I have found of a definite alterus race bird. It was
photographed during the nesting season at a location on James Bay, so it has
to be an alterus.  The photo is on Jean Iron's website. Scroll to the bottom
of this page:
http://www.jeaniron.ca/Shorebirds/2005/JamesBay/jamesbayshorebirds2.htm

Stil, the truth is that I have to leave quite a few birds unidentified as to
subspecies.

Charlie Barnard Jr.
Stratford



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