410 NORTH AMERICAN BIRDS. 



length about 5.30, wing 2.55-2.95 (2.71), tail 1.95-2.30 (2.11), 

 exposed culmen .48-.52 (.49), depth of bill at base .26-29 

 (.28), tarsus .80-.95 (.87). Hah. Coasts of southern Cahfornia, 

 Lower California, and Sonora; south, in winter, to Cape St. 

 Lucas and Gruaymas. 



544. A. rostratus Cass. Larg^e-billed Sparrow. 



d^. Bill from nostril only .32, depth of bill at base only .22 ; general 



color above dull brownish slate; length about 5.00-5.15, wing 



2.55, tail 1.95, culmen .45, tarsus .82. Hah. Vicinity of Cape 



St. Lucas 544a. A. rostratus guttatus (Lawr.). 



St. Lucas Sparrow. 



¥. Tail only two and a half times as long as tarsus, deeply emarginate, the 



lateral pair of feathers longest, the depth of the emargination equal 



to distance from eye to nostril, the feathers all narrow and pointed 



at i\]). (Subgenus Gentronyx Baird.) 



Adult : Head ochraceous or buffy, deepest on crown, nearly or quite 

 white on chin and throat ; top of head streaked with black, es- 

 pecially laterally ; maxillary stripe bordered above and below by 

 blackish rictal and submalar stripes ; lower parts white, the chest, 

 sides, and flanks streaked with black ; upper parts light brownish, 

 varied by lighter edgings and blackish spotting. Young : Similar 

 to adult, but feathers of crown and back distinctly bordered with 

 buffy, and streaks on chest less sharply defined. In imnter, the 

 buffy coloring much more pronounced than in summer, strongly 

 tingeing chest and sides. Length 5.10-5.85, wing 2.65-3.05. JVest 

 on ground, in open grassy situations, composed of dried grasses, 

 etc. £!ggs 3-5, .79 X .59, whitish (varying in tint), spotted with 

 reddish brown and lined with black. Hah. Great Plains, from 

 Dakota and Montana to the Saskatchewan in summer; south, in 

 winter, to Texas, New Mexico, and Arizona. 



545. A. bairdii (Aud.). Baird's Sparrow. 

 a^. Outer pair of tail-feathers shorter than middle pair ; difference between length 

 of tail and wing not greater than length of bill from nostril, or else tail 

 longer than wing and much graduated (" Coturniculus" leconteii), or depth of 

 bill at base equal to its length from nostril (" Coturniculus" savannarum). 

 ¥. Crown divided by a very distinct lighter median stripe, between two lateral 

 blackish ones. Nest on ground, bulky, with deep cavity, often more or 

 less arched over on top, composed of dried grasses. Eggs 3-5, white, 

 speckled or spotted, chiefly on larger end, with reddish brown, some- 

 times mixed with a few small blackish markings and touches of lilac- 

 gray. (Subgenus Coturniculus Bonap.) 

 c\ Tail double-rounded, the lateral feathers only a little shorter than mid- 

 dle pair (difference between their tips much less than length of bill 

 from nostril), the middle pair much shorter than next (longest) 

 pair-; bill stout, its depth at base equal to or greater than length 



