CHIMNEY SWIFT. 119 
tober. During the fall migrations they often gather in 
flocks of several hundred, 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. 
Whip-poor-win,  Whilethe Nighthawk is darting thro 
Antrosomus vociferus. the sky, the Whip-poor-will is nits 
Plate XXVII. == on a rock 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. 
Swirts. (FamMILy Micropopip2) 
Swirts are the most aérial of all the small land birds. 
Our Chimney Swift, the only one of the seventy-five 
Chimney members of this family that occurs in 
Chatura fers eastern North America, is but five and 
Plate XXVIIL = g half 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. 
