NIGHTHAWK. 47 1 



to capture flying insects, chiefly of the larger kind, such as 

 wasps, beetles, and moths. About the middle of May, or 

 later, the female selects some open spot in the woods, the 

 corner of a corn-field or dry gravelly knoll, on which to 

 deposit her eggs, which are only two, and committed to the 

 bare ground, where, however, from the similarity of their tint 

 with the soil, they are, in fact, more secure from observation 

 than if placed in a nest. Here the male and his mate reside 

 during the period of incubation, roosting at a distance from 

 each other on the ground or in the neighboring trees ; and in 

 consequence of the particular formation of their feet, like the 

 rest of the genus, they roost or sit lengthwise on the branch. 

 During the progress of incubation the female is seen frequently, 

 for some hours before nightfall, playing about in the air over 

 the favorite spot, mounting in wide circles, occasionally pro- 

 pelled by alternate quick and slow vibrations of the wings, 

 until at times he nearly ascends beyond the reach of sight, 

 and is only known by his sharp and sudden squeak, which 

 greatly resembles the flying shriek of the towering Swift. At 

 other times he is seen suddenly to precipitate himself down- 

 wards for 60 or 80 feet, and wheeling up again as rapidly ; at 

 which instant a hollow whirr, like the rapid turning of a 

 spinning-wheel or a strong blowing into the bung-hole of an 

 empty hogshead, is heard, and supposed to be produced by 

 the action of the air on the wings or in the open mouth of the 

 bird. He then again mounts as before, playing about in his 

 ascent and giving out his harsh squeak till in a few moments 

 the hovering is renewed as before ; and at this occupation the 

 male solely continues till the close of twilight. The Euro- 

 pean Goatsucker is heard to utter the hollow whirr when 

 perched and while holding it head downwards, so that it does 

 not appear to be produced by the rushing of the air. The 

 female, if disturbed while sitting on her charge, will suff"er the 

 spectator to advance within a foot or two of her before she 

 leaves the nest ; she then tumbles about and flutters with an 

 appearance of lameness to draw off the observer, when at 

 length she mounts into the air and disappears. On other 



