THE WHITE-THROATED SWIFT. 415 



is undertaken even as late as August if the first has ])rnven unsuccessful" 

 (Birds of Ohio). 



Save in the matter of nesting, the \"aux vSwift does not differ 

 essential!}- in habit or appearance from the well-known Chimney Swift, 

 referred to in the preceding paragraphs. It is, however, very much less 

 common and is only of local distribution, chiefly in the lower mountain 

 valleys. Local attachments are doubtless largely determined by the presence 

 of large cottonwood timber, but the birds descend to the lowlands, especially 

 after the close of the nesting season, in small ro\-ing parties, somewhat after 

 the fashion of the Cloud Swifts, with which indeed they frequently asso- 

 ciate. The}- have thus been regularly reported by West-side observers at 

 Tacoma, Seattle, and Bellinghani, and I have seen them at Blaine, and in 

 l!-ie valleys of the Xooksack (at Glacier), Skagit, Nisquallv (in Rainier 

 National Park), and Ouillayute Rivers. The only East-side records appear 

 ti) be those from the north fork of the Ahtanun-i, in Yakima County, and 

 the valley of the Stehekin. in Chelan County. 



Vaux's Swift with us nests onl}- in the hollow recesses of tall dead 

 cottonwood trees, where they glue a shallow bracket of broken twigs, 

 cemented with hardened sa!i\-a. to the curving inner wall. In California, 

 however, they are said to be adopting the wa}S of civilization, and are be- 

 ginning to nest in chimneys, after the fashion of C. pclagica. 



No. 161. 



WHITE-THROATED SWIFT. 



A. O. U. No. 425. Aeronautes melanoleucus (Baird). 



Synonyms. — Rock Swift. Mouxtaix Swift. Rocky Mouxt.mx .S"wift. 

 White-thro.\ted Rock Swift. 



Description. — Adults: Plumage black (variable, sooty brown to glossy 

 black ) : forehead and line over eye paler ; lore velvetv black ; chin, throat, breast, 

 and belly, centrally, white — also outer edge of outer primary, tips of secondaries, 

 lateral tail-feathers, and a conspicuous patch on flank, sometimes nearly meeting 

 fellow across rump; bill black. Length 7.00 (177.R) or under; wing 6.50-7.00 

 (165.1-177.8); tail 2.65 {f^■J.^,^. 



Recognition Marks. — Sparrow size but larger to appearance ; exceedingly 

 rapid flight with flashing white underparts and flank patches distinctive. 



Nesting. — "The nest is securely placed far in holes or crevices of rocks or 

 indurated earths, usually at a great height ; it is a saucer-like structure, about 

 5x2 inches, with a shallow cavity, made of various vegetable materials well 

 glued together with saliva, and lined with feathers. Eggs several, in one instance 



