CHIMNEY SWIFT. 119 



tober. During the fall migrations they often gather in 

 flocks of several himdred, and as they sail about you 

 may notice their best field mark, a white spot in each 

 wing. !Nighthawks lay two elliptical, mottled eggs on 

 the bare ground or a flat rock in open fields, and, rarely, 

 on a house top in the city. 



We see the !Nighthawk and hear the Whip-poor-will ; 



one reason perhaps why the birds are so often confused. 



WMp-poor-will While the N ightha wk is darting through 



Atitrostoiiuisvociferus. the sky, tlio Whip-poor-will is perched 



Plate XXVII. Q^ ^ rook or fence rail below, indus- 

 triously whipping out a succession of rapid whip-poor- 

 wills interspersed with barely audible chucks. When the 

 call ceases, the bird is doubtless coursing low through the 

 wooded fields and glades in its search for insects. 



During the day the Whip-poor-will usually rests on 

 the ground in the woods. Here also the eggs are laid, 

 being deposited upon the leaves. They are two in num- 

 ber, dull white, with delicate, obscure lilac markings and 

 a few distinct brownish gray spots. 



Whip-poor-wills arrive from the south late in April, 

 and remain with us until October, 



Swifts. (Family Micropodid^.) 



Swifts are the most aerial of all the small land birds. 

 Our Chimney Swift, the only one of the seventy-five 



Chimney Swift members of this family that occurs in 

 Chidura peiagica. eastern North America, is but five and 



Plate xxviii. ^ |^j^|£ inches long, while its spread 

 wings measure twelve and a half inches from tip to tip. 

 Its feet are proportionately small, and so weak that the 

 bird can rest only by clinging to an upright surface. 

 The tail is then used as a prop, its spiny-tipped feathers 

 being evidently a result of this habit. 



