Identifying Orange-crowned Warbler and Tennessee Warbler

The wood-warblers, as a group, are among our most colorful and strikingly patterned birds. But there are exceptions, and one of the most notable is the Orange-crowned Warbler. It’s a widespread bird that can be found practically everywhere in North America at some seasons, but its plain appearance makes it easy to overlook.

The breeding range extends from western Alaska to Quebec and Labrador, south in the western mountains to New Mexico and Arizona, and south along the Pacific Coast through California. It winters mainly in the southern U.S. and Mexico, with a few south to Guatemala. In many areas of the southern states, it’s the second or third most likely warbler to be seen in midwinter.

Orange-crowned Warblers are much less numerous in the east than in the west. Although they occur as migrants from coast to coast, east of the Mississippi they often elude birders in migration. This is partly because of timing: In the east, they tend to migrate earlier in spring and later in fall than most warblers. Even as far north as the Great Lakes, their fall migration is mainly in late September and October. They often forage low in brushy areas, even in stands of goldenrods, where birders might not be looking for warblers.

Their lack of obvious field marks can also make them easy to overlook, espe​cially in fall, when many other warblers also wear relatively drab plumages. The species most likely to be confused with Orange-crown — Tennessee Warbler — is quite variable in fall. It usually has a fairly plain face with a pale eyebrow, or supercilium, a little more sharply defined than that of the Orange-crown. It is often dull yellow on the throat and chest, and it shows one or two very narrow pale wing bars. Its undertail coverts, usually white, are sometimes washed with yellow. However, it never has this area brighter yellow than the rest of the underparts.

Orange-crowned Warblers vary in appearance by range. The drabbest olive-gray subspecies breeds across the north, from western Alaska to eastern Canada. In the mountains of the interior of western Canada and the western U.S., it’s replaced by another race that looks somewhat brighter. Along the Pacific Coast, from southern Alaska south through California, a fairly bright yellow subspecies takes over. Despite the variation in overall color, the same basic field marks apply everywhere, as illustrated and described in the accompanying photos and captions.

Oh, and as for its English name — males and most adult females do have a patch of orange feathers on the crown, but this patch is mostly concealed by the surrounding olive or gray feathers. You’re most likely to see it on adults in midsummer, when their feathers are worn, revealing the underlying color. It’s an intriguing thing to look for but not a useful ID point.

Like many other warblers, adult Orange-crowns from most populations go through a complete molt, replacing all the feathers, in late summer on the breeding grounds. In late winter, they have a limited molt, mainly replacing the feathers of the head. When the head feathers are in worn condition (in midsummer and sometimes in midwinter), the orange crown patch is more likely to be visible; a few orange feathers can be seen on this February bird wintering in southern Texas. Although this individual is near the dull and pale extreme for the species, its undertail coverts are still clearly yellowish, not white, and at least as bright as any other yellow on the bird.

The underparts on Tennessee Warbler can range from bright white on spring birds to bright yellow on some in fall, but on the latter, the yellow is concentrated on the throat and chest. The undertail coverts are usually white. Sometimes they are tinged with pale yellow, but in those cases, they are much paler than the chest. The center of the back is noticeably green in all plumages, and the face always shows a fairly distinct dark eyeline and pale eyebrow; the bird in this photo is near the faint extreme. The shape of the bird is also helpful: Tennessee Warbler is distinctly shorter-tailed than Orange-crowned Warbler, and this is quite noticeable with some practice.

The subspecies lutescens, averaging much brighter yellow than other populations of Orange-crowned Warblers, breeds in the Pacific Coast region from southern Alaska south through California. In migration it spreads farther east, appearing commonly in Arizona and straying as far as the Great Plains. Despite its brighter color, it resembles other subspecies in field marks. Its wings and tail are very plain, and its face pattern consists mostly of a narrow, broken eye-ring, typically yellow. The blurry streaks at the sides of its chest are often hard to see. Another subspecies, sordida, of the Channel Islands and locally on the coast in southern California, is similar but darker. It has heavier dark streaks below, including on the undertail coverts.

The brightest and drabbest subspecies of Orange-crowned Warblers both occur in Alaska. The widespread race celata breeds from far western Alaska all the way across Canada to the Atlantic shoreline in Labrador and Quebec. It’s the relatively dull olive-gray form like the one seen here. The bright yellowish lutescens is widespread in southeastern Alaska and extends north almost to the Anchorage area. This bird, photographed at Anchorage, looks typical of the drab eastern celata, but intermediate birds might be found nearby, and they might suggest the appearance of the race orestera from the mountain west. It’s tricky to try to apply subspecies names to birds in the field, but watching for such variations can add interest to birding travel.

Originally Published September 1, 2018