236 BULLETIX 17 6, UNITED STATES NATIONAL, MUSEUM 



Eggs. — The t^YO eggs of the western nighthawk are indistinguish- 

 able from those of other nighthawks, showing the same variations. 

 In shape they are between oval and elliptical-oval, usually with little 

 or no gloss, though some incubated eggs are quite glossy. The 

 ground color is dull white, or grayish white, rarely "dark" or "deep 

 olive-buff''. Usually they are quite evenly marked; some are closely 

 sprinkled with fine dots, but oftener they are covered with small 

 spots, streaks, or small blotches of "olive-brown," "sepia," or 

 "mummy brown" ; occasional eggs are marked with brighter browns, 

 such as "russet" or "hazel" ; very often there are underlying spots or 

 blotches of "pale Quaker drab." The measurements of 19 eggs aver- 

 age 30.2 by 21.6 millimeters; the eggs showing the four extremes 

 measure 33.0 by 21.1, 30.0 by 23.1, 27.3 by 2lT5, and 27.5 by 19.7 

 millimeters. 



Food. — ^Irs. Bailey (1928) says of the food of the western night- 

 hawk in New Mexico: "Ants in large proportion and also beetles 

 which are the adult forms of noted pests. Specimens taken at Fort 

 Stanton — caddice flies and gnats, together Avith injurious insects, 

 including ants, plant bugs, leaf hoppers, crane flies, click beetles, 

 wood-boring and engraver beetles, clover root weevils, and nut 

 weevils." 



Beal, McAtee, and Kalmbach (1916) say that these birds are "so 

 expert in flight that no insects can escape them. They sweep up in 

 their capacious mouths everything from the largest moths and 

 dragon flies to the tiniest ants and gnats, and in this way sometimes 

 gather most remarkable collections of insects. Several stomachs 

 have contained fifty or more different kinds, and the number of indi- 

 viduals may run into the thousands." 



Dr. Mearns (1890) writes: 



In our summer tamp, near the summit of the Mogollou Mountains, a small 

 beetle was annoyingly abundant, flying into our tents in great numbers during 

 the day, and at niglit swarming around our log fires. As the twilight gathered, 

 hundreds of these Nighthawks appeared upon the scene, preying upon the 

 troublesome insects. Careless of our presence at the fires and of the noisy 

 hilarity of camp, they flitted through the smoke with astonishing freedom from 

 diffidence, capturing myriads of the hated beetles, as they passed and repassed 

 above, between, and around us, until their flickering forms were as familiar 

 as the stirring of the pine boughs overhead, and the fanning of their wings 

 almost as little heeded. 



Field Tnurks. — There are two other races of this species, hesperis 

 and howelli.) that are likely to be seen within the range of the western 

 nighthawk on migrations ; these three races are not easy to recognize 

 in life, though henryi is lighter than hesperis and darker than 

 howelli. 



The western nighthawk can be distinguished in flight from the 

 Texas nighthawk by the position of the white wing band; in the 



