'°im"] PKOCEEDIXGS OF THE NATIONAL MUSEUM. 556 



au(l closed their eyes. This tliey rei^eated several times, but at best 

 tliey ouly made little progress, and each time on being overtaken the 

 bold one was always ready to fight. This proved to be a male; the 

 sex of the other was not ascertained, bnt probably it was a female. At 

 this age the middle claw is not pectinated. 



In the light of these observations it seems likely that in some of the 

 cases in which the Night-hawks are supposed to Inive carried off their 

 young, the latter had really run from danger, or were led away by the 

 parent birds. It is pretty well established that these will remove their 

 eggs from a dangerous locality, carrying them in their mouth, but it is 

 difticult to understand how they could so transport their young. 



On May 29, 1884, watched a Night-hawk booming a number of times 

 in broad daylight; each time, just as the boom began, the wings were 

 brought forward, so that the two together formed a half moon, with 

 the points downwards, and as well as I could discern, the tips of tlie 

 wings vibrated out of sight while the sound continued. 



The courting and mating ceremonies, apart from the booming, are 

 carried out chielly on the ground, where the male maybe seen chasing 

 his mate about and around the logs and bushes. When thus engaged 

 they do not hop, but always run, as far as I have been able to observe. 



As already intimated, the eggs, which, to the best of my knowledge, 

 never exceed two in number, are laid on the bare ground; they are 

 peculiar in being of the same shape at each end, both in fact being 

 big ends. When sitting on them the old bird will close her lustrous 

 black eyes and remain perfectly still until nearly trodden on ; then, 

 finding hei'self discovered, she will flutter off and attempt, by the 

 usual shamming of lameness, to lead the intruder away from her treas- 

 ure. According to Audubou, these birds will remove their eggs when 

 mu(!h molested. My own experience shows that they will desert the 

 eggs, but 1 have never known them to be removed by the birds them- 

 selves. 



The old theory of the Night-hawk's booming was that the souiul was 

 caused by the air rushing past the wide, gaping throat; but the present 

 idea seems to be that it is made by the wings. In support of the latter 

 I would adduce the following reasons: First, the sound bears evident 

 resemblance to the drumming of the partridge and of the snipe; sec- 

 ond, it may be accurately imitated by throwing a large nail sideways 

 through the air; and last, the following observation on the crow, a not 

 very wide-mouthed bird, points, I think, to a wrong origin for the sound. 



Toronto, May 14, 1885: While watching a crow being chased by 

 another, I noticed the foremost one dive suddenly downwards and 

 then up again ; the pursuing bird followed even more quickly, and as 

 it swooped upwards it produced at the turu a boom similar to that of 

 the Night-hawk, but duller and in a lower key, as might have been 

 expected from the larger feathers and slower flight of the crow. 



