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English:
Short-billed
Dowitcher
Japanese: america oohashishigi
Latin: Tringa melanoleuca
Date: 18/MAY/2003
Location: Bolivar
Flats, Texas
L = 28 cm, WS = 48 cm
Notes:
Top: Rusty breeding
plumage
Bottom: Grayish winter plumage
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| Cin-Ty
Lee gave me the following ID tips on this tough species. Thanks!
The top one is in fresh full alternate plumage
and the second one is in transition from basic to alternate plumage.
Unfortunately, I donft know the date the birds were photographed. Based
on my experience of studying dowitchers this spring on the Upper Texas
Coast, my guess is that the second bird was photographed in April,
whereas the upper bird was photographed sometime in May. It is
possible, however, that both birds could have been photographed on the
same day even though their molt schedules appear to be different. As
late as the last week of May, I was still seeing a few Short-billed
Dowitchers retaining considerable basic plumage remnants.
The two birds can be identified as follows. On Short-billed Dowitcher
(letfs speak of the hendersoni subspecies), the end of each scapular
and median/greater covert feather is tipped with white. The shape of
the white tips differs considerably from Long-billed. In Short-billed,
the tips form a slight gVh, whereas in Long-billed, the tops of the
white tips are flat-edged. In addition, on Short-billed, the lateral
edges of the scapular and covert feathers are fringed with pale orange
to buff (or slightly yellow), grading gradually into the white feather
tips. From a distance, this gives each feather a slightly gscalyh
appearance. On Long- billed, the flat-edged white tips, combined with
the black feather centers and smaller extent of the lateral pale
feather edges, gives an overall appearance of a gwhite-barredh bird.
All of these features are distinctive on birds in FRESH plumage, as
these are. As the birdfs plumage wears (and most of the fall migrants
in July and August or in worn alternate plumage), the white tips of the
feathers are usually absent.
In the lower photo, one can see the alternate plumage greater coverts,
which contrast with the basic median coverts and scapulars (note also
that the tertials are in alternate). In the top photo (full alternate),
the lighting is actually not very good. However, if one blows up the
photo, one can make out some of the feather patterns of the scapulars
and median coverts. Other features that are distinctive of Short-billed
are the very subtle droop to the tip of the bill (Long-billed is
perfectly straight). In the lower bird, which retains basic-plumaged
underparts, one can also see the characteristic white belly and
somewhat barred and spotted sides, characteristic of Short-billed. In
the upper figure, the lack of alternating black and white bars on the
sides of the belly rule out Long-billed (but I would only use this
field mark if the bird is in FRESH plumage). Finally, the supercilium
on Short-billed Dowitchers tends to arc more than in Long-billed
(Long-billed projects straight from the gape of the bill through and
behind the eye).
Habitat may occasionally help as supporting evidence for clinching an
identification, but I would never base my ID on habitat. In many cases,
Short-billeds winter in salt-water habitats, whereas Long-billeds tend
to prefer freshwater habitats. In migration, however, I think one
should be very careful in relying on this so-called generality. I have
seen Long-billed Dowitchers at Bolivar and even some Short-billeds at
Anahuac NWR during this past spring migration.
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