Bird of the Month: Orange-crowned Warbler
By Andy McCormick
PC: Mick Thompson (Orange-crowned Warbler)
Scientific Name: Oreothlypis celata
Length 5 in
Wingspan 7.25 in
Weight 0.32 oz
AOU Band code OCWA
The Orange-crowned is a medium-sized warbler with an olive-green back and a yellow-green chest marked by indistinct gray streaks. There is a dusky gray stripe through the eye. The undertail coverts are brighter yellow. There are no wing bars or other distinctive marks on its plumage. In short, the bird is, “Striking in its plainness” (Gilbert, et al).
However, this plain warbler is interesting in several ways. The Orange-crowned is quite a hardy warbler and will winter farther north than many other species thus shortening its migration. Pacific Flyway Orange-crowns migrate to Southern California and Western Mexico where they prefer riparian growth, pine-oak forests, and juniper and oak scrub areas (Gilbert, et al).
Also of note, the Orange-crowned Warbler is one of the earliest arriving spring Neotropical migrants. It begins northward migration in February and can arrive in Washington in early March with most birds in the area by the end of March (Gilbert et al).
In addition, there are four subspecies and the brightest of them moves along the Pacific coast. The Pacific subspecies Orothlypis cerata lutescens is a coastal bird and has the most yellow. Another subspecies O. c. orestera migrates along the mountainous areas of the Pacific Flyway. This subspecies appears more gray-headed (Gilbert et al), and can sometimes be confused with the Nashville Warbler (Bell & Kennedy) or Macgillivray’s Warbler (Dunn & Garrett). Both of these subspecies will breed in the western United States, but the other two subspecies will migrate through the central and eastern United States and breed in Canada.
The genus Oreothlypis is newly formed and refers to a kind of mountain finch. Celata is Latin for something concealed and refers to the bird’s orange crown which is rarely seen except during bathing or if the bird becomes agitated (Holoway).
The Orange-crowned Warbler is almost always found in habitat consisting of brushy clearings, shrubby thickets, or chapparal as understory in forested areas (Kaufman). It frequents stream-side thickets and shady areas. It builds an open cup nest in a small depression on the ground or on a steep bank. The nest is usually lined with dry grass or animal hair. Typically 3-4 cream-colored eggs with reddish streaks are deposited and incubated only by the female for about two weeks. The young are fed by both parents and they are ready to leave the nest in 10-14 days (Kaufman).
The song of the Orange-crowned Warbler is usually described as a high-pitched trill that loses its volume and speed toward the end. A descriptive phrase has been developed which may be helpful in remembering this song: “An orange, quickly bouncing on your crown, will eventually slow down and fall” (Stephenson & Whittle). The call note is a very sharp “stick or tik (Dunn & Garrett).
The population is considered stable and not threatened, yet some nesting areas have been disrupted by logging that damages understory in parts of Alaska and cattle grazing in oak woodland in California. It is feared these activities may be reducing breeding areas for the Pacific population of these warblers. Yet, breeding habitat has benefited from some logging which secondarily opens some forest areas and as a consequence allowed the growth of thickets and chapparal.