Original description: Emberiza bilineata Cassin 1850
Taxonomic history in AOU/AOS Check-list
AOU 1 (1886): Black-throated Sparrow, Amphispiza bilineata
AOU 2 (1895): Black-throated Sparrow, Amphispiza bilineata
AOU 3 (1910): Black-throated Sparrow, Amphispiza bilineata bilineata; Desert Sparrow, Amphispiza bilineata deserticola
AOU 4 (1931): AOU 3 (1910): Black-throated Sparrow, Amphispiza bilineata bilineata; Desert Sparrow, Amphispiza bilineata deserticola
AOU 5 (1957): Black-throated Sparrow, Amphispiza bilineata bilineata, Amphispiza bilineata opuntia, Amphispiza bilineata deserticola, Amphispiza bilineata bangsi, Amphispiza bilineata tortugae, Amphispiza bilineata carmenae
AOU 6 (1983): Black-throated Sparrow, Amphispiza bilineata
AOU 7 (1998): Black-throated Sparrow, Amphispiza bilineata
IUCN Conservation Status: Of least concern
Behavior: Black-throated Sparrows are generally unobtrusive, if not especially shy, spending most of their time on the ground in desert grassland with scattered cactus and small trees. If disturbed, they fly low into nearby vegetation, usually perching quietly and out of sight for some time before returning to the ground.
Sustained flight over longer distances is rarely seen in this species. Birds flashing across a path or road are readily identified in flight by the strong contrast between the brownish back and rump and the black tail; the white in the tail is rarely conspicuous in flying birds.
While males occasionally sing in flight, most song is delivered from a low perch, even from the ground. Cholla, prickly pear, and mesquite are favored perches.
Voice: Perched atop a bush or cactus, this species shares with the “sage” sparrows the habit of nervously twitching its tail upwards in a stiff staccato series. That motion is sometimes accompanied by a very short, often barely audible call note, a high-pitched, silvery tsit with a sharp attack and virtually no decay. The same call, repeated at irregular intervals, is given by anxious birds on the ground, but in sustained flight this species is usually silent.
The song of the Black-throated Sparrow is remarkably variable among individuals, and some males have as many as nine distinct songs. Singing begins in some areas as early as February, and is most frequent within an hour of sunrise. Most songs are simple, comprising a ticking introduction followed by a trill or buzz. In the most emphatic examples, loud and rhythmically strict, the concluding trill recalls the tremolo with which many Rufous-winged Sparrow songs end; more typically, the notes shimmer and blur like tiny cymbals touched with a brush. More complex songs insert a soft, loose buzz between the introductory chips and the concluding trill; the trill itself may be extended or repeated, either in identical form or as a series of variations.
This species is also “known to sing in flight; during song flight, wings [are] fluttered and quivered dramatically and head [is] thrown back, unlike normal direct flight.”
Detailed description and measurements drawn from standard reference works
Adult Amphispiza bilineata deserticola: Tail feathers blackish. Outermost tail feather with largely white outer web and small white tip on inner web. Upper tail coverts, rump, back, and scapulars plain grayish brown. Primaries, secondaries, and tertials grayish brown with faintly browner edges. Greater and median coverts grayish brown with diffuse darker central areas. Nape plain grayish.
Under tail coverts, vent, and lower belly whitish gray with buff tinge. Flanks and sides of lower breast pale grayish. Upper belly and sides of upper breast whitish. Throat and center of upper breast black, tapering to an irregular point on breast. Broad bright white jaw stripe borders black of throat; separated from base of lower mandible by small black spot continuous with black throat and lore.
Crown brownish gray with variable fine black lateral crown stripe. Broad white supercilium widest just behind eye, reaching to sides of nape; separated from base of upper mandible by small black spot continuous with black lore and lateral crown stripe. Ear coverts grayish, bordered below by fine short black whisker dividing ear coverts from jaw stripe. Small white crescent below eye.
Tarsus and toes dark gray. Blue-gray bill with swollen base, noticeably curved culmen.
Juvenile Amphispiza bilineata deserticola: Tail feathers blackish. Outermost tail feather with largely white outer web and small white tip on inner web. Upper tail coverts, rump, back, and scapulars grayish brown with irregularly scattered blackish streaks. Primaries and secondaries grayish brown with thin buffy edges. Tertials brownish with broad buffy edges. Greater and median coverts buffy brown with diffuse darker central areas and broad pale tips. Nape grayish with variable fine blackish streaks.
Under tail coverts, vent, and lower belly buffy white. Flanks, belly, and breast dull white, the breast with scattered short dusky streaks and flecks. Throat white with variable sparse blackish flecking; sometimes a hint of fine, incomplete lateral throat stripe. Broad bright white jaw stripe reaches to base of lower mandible.
Crown brownish gray with indistinct short dark streaks. Broad white supercilium widest just behind eye, reaching to sides of nape; flecked dusky above dark gray lore. Ear coverts grayish, bordered below by fine short darker gray whisker dividing ear coverts from jaw stripe. Small white crescent below eye.
Tarsus and toes dark gray. Pale blue-gray bill with swollen base, noticeably curved culmen.
Length 122-38 mm (4.8-5.4 inches)
Wing chord 62-71 mm (2.4-2.8 inches)
Tail 59-68 mm (2.3-2.7 inches)
W:T 1.05
