Nashville Warbler

Uncommon but regular in Sonoma County. Migrating population passes through mostly in April and May (heading north) and in September through early November (heading south). Wintering birds are by no means common, but they are reported regularly along the coast, mostly in the Bodega Bay area, notably in the trees below the elevated parking deck at Diekmann’s Bay Store. Probably an occasional county breeder. There were no confirmed Sonoma County breeding records as of the 1995 Breeding Bird Atlas, but at least one probable nesting pair is noted in that book. Active forager, especially on tips of small branches. Two distinct breeding populations exist, one on either side of the Rocky Mountains.

A smallish, plump warbler with pale grey crown, cheeks, nape, and upper back, sometimes tending toward a bluish-grey; distinct, complete, white eyering; olive to greyish-olive on back, wings, rump, and tail; no wingbars; yellow throat, breast, belly, flanks, and vent--thus, all yellow underneath except for a variable white patch at the base of the legs--more extensive in some birds than others. Often paler at the throat. Rusty patch on crown most often not visible (often ignored in field guides). Plumage variable; some birds quite brightly colored, others more drab.

In our area, most likely to be confused with subspecies of Orange-crowned Warbler (Oreothlypis celata) that have a hooded look, but Orange-crowned Warbler has a more slender, elongated shape. It has a less sharply contrasting eyering, which, importantly, is split laterally. A pale yellowish or whitish supercilium, or eyebrow, coupled with a faint eyeline give the face of an Orange-crowned warbler a vaguely horizontally striped look, whereas the Nashville Warbler’s eyering is always complete and sharply contrasting from the plain grey of the face; Nashville lacks the supercilium and eyeline. Overall, Orange-crowned warbler is a dull grey-olive with few other distinguishing markings aside from the facial characteristics described above--although paler underneath and typically with some faint streaking on the breast. Its orange crown feathers are rarely exposed. Doubtful birds usually turn out to be Orange-crowned Warblers simply because that species is so much more common in Sonoma County than is Nashville Warbler.

Selected county sightings: Diekmann’s Store (10/26/15, Colin Talcroft); Diekmann’s Store (1/16-17/15, Colin Talcroft), Diekmann’s Store (12/31/14, Dea Freid); Diekmann’s Store (10/31/14, Scott Carey); 10/12/14 (Owl Canyon, Dea Freid); Doran Beach entry area (8/24/14, Dea Freid); Pine Flat Rd. (4/23/14, Logan Kahle); Pine Flat Rd. (4/21/14, Denise and David Hamilton); Diekmann’s Store (3/24/14, Bruce Mast); Diekmann’s Store (2/15/14, Chris Dunford); Diekmann’s Store (1/6/14, Denise Herzberg)

Older sources will put this bird in the genus Vermivora as Vermivora ruficapilla. Listed in some European sources as Leiothlypis ruficapilla, a newer designation not everywhere accepted.

English synonyms: Calaveras Warbler, Gray-headed Warbler (neither used in Sonoma County)

Nashville Warbler in other languages--German: Rubinfleck-Waldsänger; Spanish: Chipe de Cabeza Gris, Chipe de Coronilla, Chipe de Nashville, Chipe gorrigris, Ciguíta de Nashville, Reinita Cachetigrís, Reinita de Nashville; French: Fauvette à joues grises, Paruline à joues grises; Russian: Красношапочный пеночковый певун; Chinese: 黄喉虫森莺; Japanese: ズアカアメリカムシクイ(zuakaamerikamushikui)

(Language information from Avibase, Birds of Europe (Mullarney et al, Princeton Field Guide Series), and Birds of Asia (Mark Brazil, Princeton Field Guide Series).