About Setophaga nigrescens (J.K.Townsend, 1837)
The black-throated gray warbler (Setophaga nigrescens) has soft, non-glossy plumage made up mostly of black, gray, and white. It is easy to identify by its striping and small yellow spot between its eye and bill. The sexes differ only slightly: both have gray upperparts with black streaks, and white underparts with black streaks on the flanks. Adult males have black striping on the crown, throat, and below the eye, with white coloring around the chin and above the eye. Adult females have duller plumage on the head, with a white throat and dark gray cheeks. The bird species that most closely resemble the black-throated gray warbler are the black-and-white warbler and blackpoll warbler, though these two have entirely different plumage patterns despite their black markings. This species is typically 13 cm (5.1 in) long and weighs 8.4 g (0.30 oz). Measured dimensions for the species are: wing length 5.6–6.9 cm (2.2–2.7 in), tail length 4.7–5.5 cm (1.9–2.2 in), bill length 8.4–9.6 mm (0.33–0.38 in), and tarsus length 1.66–1.88 cm (0.65–0.74 in), with females being slightly smaller than males. Wingspan ranges from 19–19.7 cm (7.5–7.8 in). The black-throated gray warbler produces a sharp tup or thick call, similar to the call of Townsend's warbler but flat and unmusical, as well as a high see call during flight. The male's song is a series of buzzy notes, with earlier notes doubled and the second-to-last note high. This song has three variations, including a quiet "soft song" that males sing while following females that are gathering material to build a nest. Black-throated gray warblers breed in western North America, with their breeding range stretching from southwestern British Columbia along the Pacific coast to northern Baja California, and east to New Mexico and southern Montana. Most individuals winter in Mexico, from southern Baja California to Oaxaca state. The species has only recently expanded into parts of Wyoming and Montana, as the range of Juniperus osteosperma has grown due to climate warming. Vagrant individuals have been recorded across eastern North America and in Cuba. The black-throated gray warbler breeds in open coniferous and mixed forest with a brushy understory, dry open oak forests, chaparral, and other types of scrubland. It is particularly associated with pinyon pines, junipers, and oaks. This species migrates south late in the fall, and returns north in mid-spring. During migration, it forages in any woodland or scrub it passes through. On its wintering grounds, it lives in dry woodland and tall scrub. Although the species' full status is not well understood, it does not appear to face serious threat from habitat destruction or other human activities, unlike many migratory warbler species. It is a fairly common bird, and is among the most common species in some local areas. Because it is common and not experiencing rapid population decline, it is assessed as Least Concern on the IUCN Red List.
