178 



BIRDS OF AMERICA 



that no one has yet discovered where it spends 

 the five months between the time it disappears 

 from the northern coast of the Gulf of Mexico 

 in November until it returns in March. This 

 extraordinary mystery was recorded by Wells 

 W. Cooke, assistant biologist of the Bureau of 

 Biological Survey, in his invaluable monograph 

 on Bird Migration, as follows: "Much has been 

 learned about bird migration in these latter days, 

 but much yet remains to be learned, and the fol- 

 lowing is one of the most curious and interesting 

 of the unsolved problems. The Chimney Swift 

 is one of the most abundant and best-known 

 birds of the eastern United States. With troops 

 of fledglings, catching their winged prey as they 

 go and lodging by night in tall chimneys, the 

 flocks drift slowlv south joining with other 



bands, until on the northern coast of the Gulf of 

 Mexico they become an innumerable host. Then 

 they disappear. Did they drop into the water 

 or hibernate in the mud, as was believed of old, 

 their obliteration could not be more complete. 

 In the last week in March a joyful twittering 

 far overhead announces their return to the Gulf 

 coast, but their hiding place during the interven- 

 ing five months is still the Swift's secret." 



George Gl.\dden. 

 Vaux's Swift (Cluvtura vauxi) is the western 

 representative of the Chimney Swift, ranging 

 through the Pacific coast district from British 

 Columbia to Lower California. Its upper parts 

 are sooty brown and the under parts, .gray. In 

 general appearance it is quite Bat-like and it, too, 

 flies abroad at eventide. 



WHITE-THROATED SWIFT 

 Aeronautes melanoleucus (Baird) 



A. O. U. Number 4^5 



General Description. — Length, 6-}4 inches. Upper 

 parts, sooty-blackisli witli two white patches ; under 

 parts, white. Tail, forked with the feathers narrow 

 and stiff but not spiny. 



Color. — Adults : Crown and hindneck, grayish- 

 brown to very dark sooty-brown, sometimes uniform 

 but usually becoming paler on forehead, and with 

 feathers indistinctly margined with paler, especially on 



frontal region, the projecting edges of crown, dull 

 whitish, forming a distinct narrow streak over the eye ; 

 back, shoulders, wing-coverts, rump, and upper tail- 

 coverts, plain sooty-blackish, the tail similar but rather 

 more sooty (less blackish) ; a large patch of ivhitc or 

 hrownish-zt'hitc on each side of rump, pointed in front; 

 wings, dark sooty-brown or sooty-blackish, the second- 

 aries broadly tipped on outer web with dull or brownish- 



Drawing by R. I. Brasher 



WHITE-THROATED SWIFT ( 5 nat. sizel 

 Its wonderful swiftness of wing and its inaccessible habitat insure this bird's safety -from man, at least 



