NORTH AMERICAN BIRDS. 227 



grounds along the banks of streams. Begins laying the last of May, 

 depositing two white, unspotted eggs upon the bare ground, in the 

 thick growth at the edge of timber ; also at the roots of a bunch of 

 bushes or briers upon the prairies. Mr. Emerson states that he fre- 

 quently heard this bird's mournful cries, poor-will, poor-will, in San 

 Diego county, California, in the month of April. A set of two eggs in 

 his collection, taken near Manhattan, Kansas, May 28, 1885, are pure 

 glossy-white, and measure 30x22, 30x22.5 mm.* 



419. Nyctidromus albicollis (GMEL.) [356.] 



Parauque. 



Hab. Valley of the Rio Grande and southward. 



Dr. James C. Merrill, Assistant Surgeon U. S. Army, first added 

 this species to our fauna in 1876. In the vicinity of Fort Brown it was 

 a common summer resident, arriving early in March and remaining as 

 late as the middle of November. It frequents shady thickets and 

 copses, and when flushed dodges rapidly and silently among the 

 bushes, but soon alights. In these places the eggs are deposited 

 usually at the foot of a bush. Dr. Merrill observes that the habits 

 and eggs of this species, in addition to its anatomical charac- 

 ters, show its affinity with the Whip-poor-wills rather than the Night- 

 hawks. Their notes are among the most characteristic night sounds 

 of the lyower Rio Grande, and are constantly heard at evening during 

 the summer months. They consist of a repeated whistle, resembling 

 the syllables whew, whew, whew, ^vhew, whe-e-e-e-e-w , much stress 

 being laid upon the last, which is prolonged. The whole is soft and 

 mellow, yet can be heard at a great distance. Mr. George B. Sennett, in 

 the same region in Southern Texas, obtained a set of two eggs, April 

 20. He states that the birds breed in the more open places among the 

 cactus and scattered bushes along with C. lexensis Texas Night- 

 hawk. The eggs are two in number, of a rich creamy-buff, sparingly 

 marked with a deeper shade of the same, and with lilac ; average size 

 i. 25 x. 92. Their size and creamy-buff color render them easy of 

 identification. 



On the 1 5th of May, Dr. Merrill found a set of eggs of this species 

 near camp at Hidalgo, and on returning in about fifteen minutes to 

 secure the parent, who had disappeared among the thickets, he found 

 that she had removed the eggs, although they had not been touched. 



420. Chordeiles virginianus (GMEL.) [357.] 



Niglithawk. 



Hab. Eastern North America, north to Hudson Bay, west to the edge of the Great Plains, south 

 through tropical America. 



The Niglithawk, Bullbat, or Goatsucker, as it is variously called, 



* 1.18 x .87, 1.18 x .91. 



