OF NEW ENGLAND. 299 



like it, except the notes of one or two other birds. It is very 

 striking, and, if heard from a near standpoint, rather startling. 

 The male Night "Hawk" produces an equally extraordinary 

 sound, which is heard chiefly during the season of courtship. 

 Mounting to some height, he falls, head foremost, until near 

 the ground, when he checks his downward course, and then 

 the "booming" is heard, a sound "resembling that produced 

 by blowing strongly into the bung hole of an empty hogshead." 

 I am uncertain as to what causes this noise, having found it 

 impossible to make any close observations. Wilson thought it 

 produced by the mouth, Audubon, by the concussion caused 

 by a change of position in the wings. The Night "Hawks" 

 all leave New England in September. 



§21. Cypselidse. Swifts. (See §20.) 

 I. CH^TURA 



(A) PELAGiCA. Chimney Swift. Chimney '■'■Swalloio." 

 (A common summer-resident throughout New England.) 

 (a). About five inches long. Sooty-brown, glossed with 

 green above ; throat, much paler. Lores and wings, black. 



(6). The Chimney "Swallows" soon after their arrival con- 

 struct their curious nests, which are composed of twigs firmly 

 glued together by " a fluid secreted with the birds." These 

 nests are now placed in chimneys, almost universally through- 

 out civilized parts of the country, but they have been found 

 attached to boards, and the eggs were originally laid in hollow 

 trees or stumps. The eggs of each set are four, average '70 X 

 •50 of an inch, and are pure white, unmarked. 



(c). The Chimney Swifts possess powers of flight which are 

 probably unsurpassed by those of any bird not belonging to 

 this family. It is almost certain that they often fly no less 

 than a thousand miles in the course of twenty-four hours. 

 "When providing for their j'oung, they ax'e sometimes busy dur- 

 ing a greater part of the day, and even continue their labors 

 at night. Usually, they become active at a very early hour, 

 sometimes even before dawn, and retire during the warmer 

 part of the day, unless it be cloudy, when they continue their 



