BIRDS OF PENNSYLVANIA. 
179 
Genus ANTROSTOMUS Gould. 
Antr ost omus vocif er us ( Wils . ) . 
Whip-poor-will. 
Description {Plate 2S). 
Length about 10 inches ; extent about 18 ; gape with long stiff bristles reaching be- 
yond bill ; no white spot on primaries. 
Habitat . — Eastern United States to the plains, south to Guatemala. 
Although the Whip-poor-will and Nighthawk are generally regarded 
by those who are not versed in ornithology, as the same bird, it can 
readily be seen, by referring to Plate 23, that they differ greatly. It 
will be observed that the Whip-poor-will has conspicuous, long and stiff 
bristles at the base of bill ; the bill of the Nighthawk is not furnished 
with long, conspicuous and stiff bristles. The Whip-poor-will has no 
white spot on the ]Drimaries ; the Nighthawk has a well-marked spot of 
white on five outer primaries. The white on tail of males of both species 
is also different. In the Whip-poor-will the lower half of the three outer 
tail feathers is white ; Nighthawk has a broad white bar crossing the 
tail (except middle feathers) near the tip. The males, both species, 
have transverse white throat bars. The female Whip-poor-will has a 
tawny throat bar, and inconspicuous terminal spots of the same color 
on lateral tail feathers. Female Nighthawk, throat bar tawny, white 
spot on wing, but no terminal patch of white crossing tail. 
The Whip poor- will is a rather common summer resident in the wooded 
and mountainous portions of Pennsylvania. It arrives in this locality 
from April 22 to May 1, and migrates southward in September. The 
Whip-poor-will migrates singly or in pairs, and, unlike the Nighthawk, 
is never to be found in fiocks. The Whip-poor-will is nocturnal in hab- 
its, and is seldom seen during the day unless accidentally discovered 
in a state of repose, when, if startled, “it rises and flies off, but only 
to such a distance as it considers necessary, in order to secure it from 
the farther intrusion of the disturber of its noon-day slumbers. Its 
flight is very low, light, swift, noiseless and protracted, as the bird 
moves over the places which it inhabits, in pursuit of the moths, beetles 
and other insects of which its food is composed. During the day it 
sleeps on the ground, the lowest branches of small trees, or the fallen 
trunks of trees, so abundantly dispersed through the woods. In such 
situations you may approach within a few feet of it ; and, should you 
observe it whilst asleep, and not make any noise sufficient to alarm it, 
it will suffer you to pass quite near without taking flight, as it seems to 
sleep with great soundness, especially about the middle of the day. In 
rainy or very cloudy weather it sleeps less, and is more on the alert. 
Its eyes are then ke^Dt open for hours at a time, and it flies off as soon 
as it discovers an enemy approaching, which it can do, at such times, at 
