Identification of Dowitchers in the Pacific Northwest
Why don't shorebirds ever look like the pictures in the field guides? Well, the illustrations in the field guides are simplified to make it easier to identify typical individuals. But shorebirds are not simple, and these field guides, being very brief in nature, often confuse rather than enlighten.
Three field guides are adequate when it comes to shorebirds. The first is the National Geographic Society's Field Guide to the Birds of North America (hereafter, NGS guide), third edition (2002). The second is the Audubon Society's Master Guide to Birding (hereafter, the Master guide), edited by Ferrand (1983). And the third is The Sibley Guide to Birds published by the National Audubon Society (2000). Kaufman's Advanced Birding (1990) is helpful. Paulson's Shorebirds of the Pacific Northwest (1993) is very good. Much useful information on dowitchers was found in the article, "The identification and migration of breeding plumaged dowitchers in southern Ontario," by Jaramillo, Pittaway, and Burke, as found in Birder's Journal 1(1):8-25, Oct. 1991.
Breeding plumaged adult Short-billed and Long-billed dowitchers migrate through the Pacific Northwest in spring and fall. In addition, many Long-billed Dowitchers winter in this area as well. In the fall, juvenile dowitchers of both species migrate south through the Pacific Northwest.
In general, Short-billed Dowitchers prefer saltwater situations, while Long-billed Dowitchers prefer fresh water puddles. Even so, Long-billeds can be found in the estuaries, and a few Short-billeds migrate through the interior of our region.
Female dowitchers have longer bills than males. Female Long-billed Dowitchers have the longest bills and male Short-billeds have the shortest. But there is almost total overlap between the male Long-billeds and the female Short-billeds. In a flock, the longer billed dowitchers are females, but not necessarily Long-billed Dowitchers.
Of the three races, or subspecies, of Short-billed Dowitchers, caurinus is the expected form in our region, though hendersoni is rare both in spring and fall as adults, and in the fall in juvenal plumage. Long-billed Dowitcher has no subspecies.
Contrary to what the field guides indicate, probably only the interior race of Short-billed (hendersoni) consistently has more white than black on the tail. The Atlantic form (griseus) and Pacific form (caurinus) of Short-billed has as much, or more, black than white on the tail--thus identical to Long-billed Dowitchers. This feature is only visible when the tail is fanned (such as in flight), as uppertail coverts conceal most of the tail at rest. Thus, for most West Coast dowitchers, the amount of white in the tail is not a useful field mark.
Fresh breeding plumaged (also called alternate plumaged) dowitchers migrate north from April to mid-May. Dowitchers at this time of year will probably retain some gray covert feathers from the non-breeding plumage (also called basic plumage) [see Figure 1]. These feathers will grow in by early summer, completing the molt.
The key marks on Long-billed Dowitchers at this time of year are the heavily spotted throat and the barred upper breast. In very freshly-plumaged birds, the white terminal tips outside the black subterminal bars [see Figure 2] give a frosty look to the underparts, which are entirely reddish-orange.
The breeding caurinus Short-billed is pinkish-red with a variable amount of white on the belly. The flanks are heavily barred, and the breast is densely spotted. The upperparts are narrowly edged with reddish.
The underparts of breeding hendersoni Short-billed is also pinkish-red below. But this pinkish wash extends to the entire underparts, including the belly. The flanks and sides of the breast are lightly spotted. The feathers of the upper parts (back, scapulars, and tertials) are broadly edged and patterned with golden, washed with reddish on the scapulars.
Note that the photograph in the Master guide labeled: "griseus" is most likely caurinus. Therefore this book conveniently has a breeding plumage photo of both of the races of Short-billed Dowitchers likely in our area.
Adults in fall
Adult dowitchers start returning south soon after the eggs hatch. As hard as is is to believe, Short-billed Dowitchers are already moving south through our region by late June! Long-billeds generally trail Short-billeds in fall migration by 3 weeks (or more).
Adult Short-billeds migrate through the Pacific Northwest from late June to mid-August.
Adult Long-billeds have an extended migration. They are common in breeding plumage all through July and on to mid-September. They may stop in the Pacific Northwest, interrupting their migration, to molt into basic plumage, then continue their southward migration.
Breeding plumaged fall Short-billed Dowitchers are quite similar to spring plumaged birds. The underparts are pinkish, with perhaps more white on the belly. The spots on the breast are still distinctive. The upperparts on caurinus may be darker as the edges wear from the dark-centered mantle feathers. The rare hendersoni, however, will be golden and black striped, as the golden edge patterns reach all the way to the feather shafts.
The "frosty" white tip of the breast feathers on the Long-billed Dowitchers wear away early in the breeding season. By fall, the subterminal black bars begin to wear away. Worn adults, then, will lose much of the barring from their breasts.
A fall adult with little or no color on the underparts, but retaining extensive thick, solid alternate breast markings is almost certainly a Short-billed, while a fall adult retaining smooth reddish color throughout the underparts including the belly, but with very thin-looking, worn breast markings is almost certainly a Long-billed.
Juveniles (young birds in their first set of feathers after the downy plumage) are the easiest dowitchers to tell apart. The plumage is fresh and new with crisp, bright, colorful edges--very unlike the worn and faded adult fall dress.
Juvenile Short-billeds arrive in early August and migrate through until the end of September. Juvenile Long-billeds arrive in early September and remain in this plumage into November. They then molt sequentially into basic plumage. The tertials are among the last feathers to molt.
Juvenile Short-billed Dowitchers are very bright and highly colored. The upper breast is bright buff with spots, fading to white on the belly. The scapulars and tertials are widely fringed and patterned with reddish [see Figure 3]. The coverts are barred and fringed with buff.
Long-billed Dowitcher juveniles are rather plain. The scapulars have cinnamon margins, but the coverts and tertials have thin buff margins. The breast is buff and gray with little spotting, which fades into a white belly.
Dowitchers in basic plumage (also called, inaccurately, "winter" plumage) are rather gray. Adults molt into this plumage in late September, while juveniles do so in late November. They keep this plumage into March. Late April and May records of dowitchers in basic plumage are likely first-year Short-billed Dowitchers, which will not breed, and may not migrate all the way north. This seems less common with Long-billed Dowitchers.
Fall Short-billed Dowitchers migrate to their wintering grounds, south of the Pacific Northwest, before completing their molt to basic plumage. Thus, all basic plumaged dowitchers in fall and winter in the Pacific Northwest should be Long-billed. The plain gray upperparts are matched by the extensive unspotted gray wash on the breast.
Any basic plumaged Short-billed Dowitchers in the Pacific Northwest need to be carefully documented. This is the hardest plumage in which to separate the two species. The gray wash on the breast of Short-billed might be paler and less extensive, with some spotting. The primary projection [see Figure 1], a short way past the tertials, might be a supporting detail. The voice would have to be well heard and described. Some Short-billed Dowitchers regularly winter as far north as southern California, so some may be expected in the southern coastal areas of the Pacific Northwest as well.
This is the best field mark. Even so, many people are confused by it. The call of Short-billed is typically a quick, mellow, tu-tu-tu, similar to Lesser Yellowlegs. The call of Long-billed is a sharp keek, usually given singly, but often repeated. These calls are usually given in flight, though Short-billeds often fly silently.
Long-billed Dowitchers give a variety of low feeding notes, but Short-billed Dowitchers usually feed silently. Both species in spring may break into a similar sounding trilling display flight song. The NGS guide tape recording has proved quite useful for some in learning dowitcher calls.
This article is an updated version that was originally published as "Dowitchers" in the The Bird Guide, Vol. 2, No. 2, August 1995.