I’ve been looking through eBird checklists that include
Short-billed Dowitchers and a number of comments reminded me
just how challenging it can be to ID breeding plumage adult
dowitchers so I thought I’d throw out some things that have
helped me.
Before I get started I want to point out that the Andrew
Birch / Cin-Ty Lee article which was published in Birding
magazine has been widely criticized, for good reason. When I
first became aware of it I was very excited. I read and
reread it, studied the new “field marks”, and when spring
came I went out to pick through dowitchers (more on this
later). Long story short, I found the article almost useless
and was glad when others voiced their concerns about the
field marks it presented. So, buyer beware. I won’t go
into details but I will say the only thing in the article
that seems consistent (read useful) is the kink in the bill
of Short-billed about 1/3 of the way back from the tip.
It’s a sharp kink, not an even curve. Long-billeds also can
have a droop but it’s less restricted (or more curved than
kinked if that makes any sense?) and more towards the center
of the bill. The kink is not always present but so far I’ve
only seen this on birds that could be identified as
Short-billeds using other field marks.
Rather than start from scratch I’m going to copy some of
what I’ve written in the past but I want to start by
pointing out that the most important step when trying to ID
dowitchers (or any shorebirds) is aging the birds. It’s
surprising how many ebird checklists include comments
describing striped tertials on adults and spots on breast
sides of juveniles. Both are irrelevant. Right now there are
only adults – there are no juveniles in spring and adults of
both species have stripes on their tertials. When fall
migrants begin to appear you can find either age but they’re
easy to tell apart because the adults are worn and the
juveniles are in fresh plumage.
That said here are some thoughts on identifying adults in
spring. Primary extension can be helpful but it is variable
and some SBDOs do not show much, or any, extension beyond
the tail. The right hand bird in this photo is a good
example:
<ivZi1pLB3b10EFbl.png>
I still struggle with breeding plumage dowitchers but there
are some things that seem to work.
-Spots on the side of the breast. The left hand bird in the
above photo has distinct spots on the side of the breast ahead
of the wing. These spots are on the feather shaft well away
from the tip of the feather and are diagnostic if present.
-SBDO often shows quite a bit of white on the belly, flanks
and/or vent, again like the left hand bird above. Here’s
another example that also shows obvious spots on the breast
sides:
<tAEmf05baKhwt8CF.png>
-Orange of underparts is paler and more orange on SBDO, not as
dark and rufous as LBDO.
-SBDO has less black spotting on the center of the throat,
often clean, unmarked orange that’s quite distinctive. Here’s
another photo that illustrate these last two points (right
hand bird).
<s8Oh7q5FLoH80EN4.png>
-Bill of SBDO often appears slightly drooped near the tip, but
I’ve seen a couple LBDOs that appear to have a slight droop as
well, albeit further from the tip of the bill, so I would
suggest using this with caution.
-Markings on edges of feathers and internal markings on
scaps/coverts of SBDO are often paler golden buff than the
rufous of LBDO.
Hopefully you’ll find some of this useful. I still try to
verify identification by flushing possible SBDOs hoping they
call and still leave some as ???
I recently found these pages that seem useful:
http://tgreybirds.com/Pages/LongbilledDowitcherp.html
http://tgreybirds.com/Pages/ShortbilledDowitcherp.html
– this page details a Short-billed field mark I hadn’t seen
before. The pale tips of the flank feather are washed
orange, not bright white as on Long-billed. So far this
seems to be consistent but I don’t know if it’s totally
reliable.
Now I want to revisit the Birding article. I went out and
tried to apply the new field marks and became skeptical of
their validity so I posted some photos to the ID Frontiers
listserv requesting opinions. I’m going to put the photos
below but withhold my guesses on the IDs and what the
experts had to say for now. If you’re up for the challenge
take a look and try to ID them and see if you do better than
I did. Which do you think are Long-billed and which are
Short-billed?
These photos were all taken on Island Park Reservoir in
Idaho.
<twobirds.jpg>
Photo #1: This was taken on May 27
<dow3.jpg>
Photo #2: This one was taken on May 20
<dow1.jpg>
<tail1.jpg>
Photos 3 & 4: Taken on May 14
<dow2.jpg>
<tail2.jpg>
Photos 5 & 6: Taken on May 14
--
Cliff and Lisa Weisse
Island Park, Idaho
cliffandlisa@...
