October 19th, 2005. Hatfield/Whately townline, MA.
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Controversial White-rumped Sandpipers Calidris fuscicollis.
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Mark Taylor's original image taken on October 19th, 2005.
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Update - January 9th 2006.
When
Mark Taylor originally sent me an image (above) of a couple of digi-scoped
sandpipers on the Hatfield/Whately town line, I took a cursory glance
and felt sure that I was looking at a couple of Baird’s Sandpipers.
Mark Taylor and Bob Beida had apparently been birding together at the
site, and had seen the two birds in question rather briefly. They were
divided in thier opinion - one thought White-rumped and the other
thought Baird’s! Neither saw the rump pattern well enough to clinch an
identification on the spot.
Very few October records of Baird’s Sandpiper exist for Western
Massachussetts, and I asked Mark for his permission to post the images
on the Keenbirding website. No sooner had the images gone live, than
questions began to return about the identification. Some thought that
the identification of Baird’s was good, but others thought that
White-rumped, or even Pectoral Sandpiper should be considered. It
became clear that viewers of the images were rapidly developing
differing opinions, and to settle the matter, or so I thought, I asked
for opinions from the ID-Frontiers listserve.
It came as no surprise that birders replied to me on and off-list
strongly in favor of Baird’s. That’s until Killian Mullarney entered
the discussion on October 30th with a very different approach. He
added captions to Mark’s original image to illustrate his points and
slowly changed the flow of opinion. The discussion continued, but
despite Killian’s excellent presentation, many were still in favor of
Baird’s. Of those who actually committed firmly to an opinion, we ended
up with 25 versus 9 in favor of Baird’s to White-rumped. However, this
was only a tiny fraction of the 1200 or so unique viewers of the
Whately Sandpipers images. Many birders discussed the identification
privately but just ‘sat on the fence’. Fair enough.
In a final private exchange of emails, despite the majority still very
much in favor of Baird’s, Killian remained firm in his opinion. After
reading his last email on the subject and reviewing another captioned
image, I finally acknowledged my own error and agreed that the birds
were indeed White-rumped Sandpipers.
Many interesting thoughts came out of this discussion which I found
tremendously valuable and I have absolutely no regrets about raising
the discussion. On the contrary, it was one of the better personal
learning experiences during the whole year.
I’m especially grateful to all the birders that took part in the discussion but especially to Mark Taylor and Killian Mullarney.
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From Killian Mullarney; excerpts from his final words on the matter, along with another captioned image.
“Hi again James!
Well, I have had another look at the photo, and I'm afraid I still find
it difficult to reconcile these with Baird's! I question the validity
of the 'field-marks' that have been chosen to support the
contention that they are Baird's. Is the clearly demarcated buffy
breast associated with Baird's really all that different to what can be
seen on some 'warm' juv White-rumps? Do you not think it is
possible that an out-of focus W-r Sand could look similar in this
respect, to what we can see on the front Whately bird?
At the risk overanalysing the photograph, there are one or two more features I'd like to draw your attention to:
You mentioned, in your email "I don't see strong rufous tones in the upper scaps"
Might this be because, on the front bird, the upper scapulars are
barely visible, and what little of them that is visible is along the
highlighted 'upper edge' of the bird, making their colour very
difficult to discern. Actually, I believe I CAN see a hint of warmth
here, but it is a very tenuous impression! I wondered if the bird at
the back might already have moulted its third row of scapulars, as
there appears to be a plain grey 'strip' here, and these generally are
the first scapulars to be moulted in calidrines. Might there also be
just a hint of warmth on the rear crown of the front bird?
More than anything else, I think it is the overall look of the
scapulars/wing coverts on the front bird that says to me "this is a
White-rumped". I guess the best thing to do is forget about it for a
while, and come back to it maybe next autumn, with fresh eyes. I hope
you don't mind me sending you one more captioned copy of the photo.
I fear that we are close to the point of flogging a dead horse on this
one, so don't feel the need to put yourself through the wringer any
more!
Sorry to have taken so long to finish this reply,
All the best,
Killian"
|  | Captions appear courtesy of Killian Mullarney, the image appears courtesy of Mark Taylor.
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| These images of a juvenile White-rumped Sandpiper were taken by Eric Dempsey in Ireland in October
2005. Note the
rather well-defined pectoral band, similar to Baird's Sandpiper. Killian has
slightly blurred the breast colour on the inset image, to demonstrate how
similar the out-of-focus impression is to that of the closer of the
two sandpipers photographed at Whately.
(Images appear by courtesy of
Eric Dempsey).
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| Another image of the Irish White-rumped Sandpiper showing a rather clear-cut
breast-band, as well as the bright rufous sub-terminal edge to the inner greater
coverts (See the captions on the Whately sandpiper image). Swords, Co Dublin, Ireland. (Courtesy of
Eric Demspey).
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| These video-grabs were taken at distance by Nic Hallam. They serve to illustrate how well defined the breast band of juvenile
White-rumped Sandpiper can appear under less than perfect conditions.
Also note how 'scaley' the upperparts appear in the first image in this
sequence.
Radley, Oxfordshire, UK. October 28th, 2005.
(Above and below, six video-grabs appear by courtesy of Nic Hallam) | 
| | Juvenile White-rumped Sandpiper. Radley, Oxforfshire, UK. November 5th, 2005. | | Images appear by courtesy of Mark Taylor, Eric Dempsey and Nic Hallam, with captions by Killian Mullarney. |
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