THE GENUS CHOBDEILES SWAINSON OBERHOLSEK. 49 



Like Chordeiles virginianus virginianus, this nighthawk lingers 

 late in the spring south of its breeding range. A single typical male 

 taken at Johnson Lake, Valley County, Montana, June 3, 1910, and 

 another obtained at Saratoga, southeastern Wyoming, June 7, 1911, 

 are evidently both but transients. So are also one taken by Alex 

 Wetmore at Greybull, in Bighorn County, central northern Wyo- 

 ming, June 14, 1910, and another at the same locality on June 15 

 of the same year, for the breeding bird of this region is Chordeiles 

 virginianus howelli; and, furthennore, Mr. Wetmore assures us that 

 the species had first arrived in this valley only a few days previous, 

 and appeared to be on the move. Likewise the autumn migration 

 begins very early, sometimes, at least, by the middle of July, thus 

 before the breeding season is over, as the following records of prac- 

 tically typical specimens indicate : One taken, July 14, 1909, at Wins- 

 low, Arizona, by C.-Birdseye; one, August 3, 1904, at Tres Piedras, 

 New Mexico; one, August 11, 1902, in the Huachuca Mountains, 

 Arizona, by H. S. Swarth; one, August 18, 1909, at Tuba, Arizona, 

 by E. W. Nelson; and another, September 1, 1908, in Buckskin 

 Valley, Iron County, Utah, by W. H. Osgood. 



It has been reported from Poway, San Diego County, California, 

 during migration, but apparently not certainly from Lower Cali- 

 fornia. Three specimens collected by Dr. C. W. Richmond on the 

 Escondido River, 50 miles above Bluefields, Nicaragua (No. 128370, 

 U.S.N.M., adult male, Sept. 17, 1892; No. 128371, U.S.N.M., adult 

 male, Sept. 17, 1892; and No. 128373, juvenal male, Oct. 28, 1892), 

 are apparently typical Chordeiles virginianus hesperis. The last 

 one (No. 128373) is the example mentioned by G. K. Cherrie^ as 

 like the type of his new race, Chordeiles virginianus aserriensis, but 

 darker. An adult female (No. 27101, Field Mus.) from Miravalles, 

 Costa Rica, is certainly Chordeiles v. hesperis, although M. A. Car- 

 riker, jr., has recorded it as Chordeiles virginianus virginianus.^ 



This nighthawk breeds chiefly during June and July, sometimes as 

 early as May 24; at Big Stick Lake, near Maple Creek, Saskatche- 

 wan, Dr. L. B. Bishop found eggs on July 19, 1906. According to 

 Joseph Grinnell it breeds chiefly in the Canadian Zone, though also 

 in the upper part of the Transition Zone, in the San Bernardino 

 Mountains of southern California. In other localities, however, it 

 nests regularly all through the Transition Zone and also in the 

 Upper Austral Zone. 



Specimens examined. — Specimens to the number of 120 have been 

 seen, from the localities in the subjoined list: 



Alherta.—Msinj Island Lake, near Walsh (July 13, 1906). 



Bntish Columhia.— Trail (June 13, 14, and 16, 1902). 



lAuk, vol. 13, April, 1896, p. 136. 



2 Ann. Carnegie Mus., vol. 6, 1910, p. 501. 



