Long-billed Dowitcher, Limnodromus scolopaceus

Long-billed Dowitcher
It's often hard to distinguish between Long-billed and Short-billed Dowitchers, even in spring breeding plumage. And the species are usually impossible to tell apart by visible marks in non-breeding plumage, the only reliable distinguishing feature being vocal, the mellow "tu-tu-tu" call of the Short-billed vs. the high piercing "keek" of the Long-billed. The bird above illustrates some marks that allow identification of a spring breeding-plumage dowitcher as Long-billed. Best of all, it has the diagnostic "frosty" look to its breast and flanks that is given by the white tips on fresh breeding feathers. Another decisive mark is the bars on the side of the breast, where a Short-billed would have spots -- but note that both species can have spots in the middle of the breast, and bars on the flanks. A third mark is the "squared-off" look to the scapulars and wing coverts with white linings; these linings are mostly confined to the bottom of the black feathers, where in a Short-billed they would normally run further up the sides, giving the feathers a more "v-shaped" look. Finally, the striped tertials completely cover the primaries at the rear end of the bird; in a Short-billed there is usually a dark spot where the primary tips extend beyond the ends of the tertials.

A good general treatment of identification issues is the chapter on dowitchers by Claudia Wilds in Kenn Kauffman, Advanced Birding. I'm especially grateful to Alvaro Jaramillo for his help in analyzing the field marks of some of birds shown on my two dowitcher pages.

Long-billed Dowitcher
Bill length can be used to identify dowitcher species only at the extremes; only "very long" and "very short" mean Long- and Short-billed respectively. How long is "very long"? After you look at thousands of dowitchers, you'll get a feel for it, one is told, but I don't have that feel yet. The bird above certainly has a shortish bill for a dowitcher, but not short enough because the plumage shows the white-tipped "frosty" look that is diagnostic of Long-billed. A dowitcher whose bill length does allows a species ID is the juvenile Long-billed at the bottom of this page. (How do I know that longish bill is long enough to be "very long?" Alvaro Jaramillo, who has looked at thousands of dowitchers and written articles about them, told me it was.)

Long-billed Dowitcher
Above, one more Long-billed in spring with the diagnostic white-tip fringes to the fresh breeding feathers, the "squared-off" scapulars and wing coverts, and a couple of breast-side bars visible among the retained gray non-breeding feathers. The white feather tips wear off quickly, and dowitchers returning from the nesting grounds in "fall" (which starts for dowitchers in midsummer) can't any longer be identified using this handy mark, making breeding-plumage ID even more difficult in fall than in spring, as with the bird below.

Long-billed Dowitcher
For fall dowitchers on the west coast, solid red underparts extending all the way to the tail, as in the bird above, are a good mark for Long-billed, though not diagnostic as a few Pacific (caurinus) Short-bills also show solid red. Most Short-billed are a relatively pale orange, and many have white underpart patches in breeding plumage. Most Prairie-Atlantic (hendersoni), found mostly in the midwest and southeast, are solid red below, so this mark doesn't work in those regions. The Atlantic (griseus) Short-billed is never solid red underneath, but hendersoni is possible over much of its range. While red is good for Long-billed, once a bird has begun to molt, a solid white area on the underparts doesn't prove the bird is Short-billed, as both species are white underneath in non-breeding plumage. A further identifying mark for the bird above is that it has few dark marks of any kind on the breast, flanks, and underparts, where there would normally be more such marks on a Pacific Short-billed; the dark spots and bars on Long-billed are closer to the edge of the feather and so more quickly worn off. A final mark clinching the Long-billed ID is the remaining bars (rather than spots) on the side of the breast. (Both species can have spots in the middle of the breast, and bars on the flanks; only for the breastside marks does the distinction between bars and spots allow species ID.)

Long-billed Dowitcher
This bird shows the red (rather than orange) and smooth underparts characteristic
of a Long-billed Dowitcher in fall. Almost all of the underpart dark marks have
been rubbed off, which would be rare in a Short-billed. The bird also shows
the flexible bill tip found in both species of dowitchers, which enables them to
take small food items out of the deep mud they probe without having to open
their bills.

Long-billed Dowitcher
This bird shows a mark for Long-billed Dowitcher that is often concealed: the barring pattern on the tail. All Long-
billed have dark bars wider than the light bars, where most Short-billed have the opposite pattern, with most of
the exceptions coming in the East Coast subspecies griseus.

Long-billed (?) Dowitchers
The one bird in this group showing substantial breeding plumage is all-red underneath, and has white underwing lesser coverts, identifying it as a Long-billed. The others, showing no color underneath, could well be juvenile Long-billed, which are expected migrants by late August. They could, however, be adults of either species that have fully or mostly molted to non-breeding plumage. I don't have any evidence that dowitchers in migration are much more likely to flock with their own species; in winter they are, because they tend to settle down in different habitats, with Short-billed preferring salt water and Long-billed preferring fresh.

Long-billed Dowitcher
This bird shows solid white underwing lesser coverts, where the same feathers on a Short-billed would be barred. This feature, visible only in flight or when the bird raises its wings, is one of the few diagnostic plumage differences between the dowitcher species in non-breeding plumage. Thanks to Michael Todd for pointing this out to me; the distinction is illustrated in Sibley's drawings.

Long-billed Dowitcher
The bird above has mostly molted into non-breeding plumage, and when that molt has finished, there will be no way to distinguish it from a non-breeding adult. However it still shows some retained juvenal Long-billed scapulars, the dark brown feathers with cinnamon linings scattered on the side of the back; these establish the bird as a first-winter Long-billed. Also, this is the relatively rare dowitcher that can be assigned to species by bill length; an expert has assured me that the bill is actually "very long" enough to be able to identify this as a Long-billed. Note, though, that I needed expert advice on this question.