WESTERN BURROWING OWL 389 



dusky; bare skin shows between the feather tracts, even after the 

 juvenal plumage has begun to grow. This first plumage seems to 

 appear almost simultaneously on all the feather tracts and on the 

 wings and tail. By the time the young bird is half grown it is competely 

 covered with the distinctive juvenal plumage. In this plumage, the 

 crown, hind neck, and back are plain, dull, grayish brown to buffy 

 brown, most grayish on the head; the wing coverts are mostly light 

 buff, but the rest of the wings and the tail are like those of the adult ; 

 the under parts and upper tail coverts are pale buff and unspotted, 

 with a suffusion of "wood brown" across the upper chest. This plum- 

 age is worn until July or August, when a complete molt of the contour 

 plumage begins on the sides of the breast, the scapulars, and wing 

 coverts; this molt is completed in September, when the first winter, 

 or practically adult, plumage is acquired. 



Adults have a complete annua] molt in August and September. 

 Many birds show so much fresh plumage in spring that I suspect 

 they may have a partial prenuptial molt of the body plumage, though 

 I have not been able to detect it. The wear and tear on the plumage, 

 owing to subterranean life, might well make such a change desirable. 



Food. — The burrowing owl is unquestionably one of our most bene- 

 ficial birds of prey, for it destroys very few small birds, mainly to feed 

 its young, and it subsists almost entirely on insects and injurious 

 rodents, which it destroys in enormous numbers. Fortunately most 

 ranchmen and farmers appreciate this fact and do not persecute it. 



Its insect food includes grasshoppers, locusts, beetles, Jerusalem 

 crickets, mole crickets, black crickets, caterpillars, dragonflies, and 

 various other insects, many of which it catches on the wing. Major 

 Bendire (1892) says: 



They hunt their prey mostly in the early evening and throughout the night, 

 more rarely during the daytime. As soon as the sun goes down they become 

 exceedingly active, and especially so during the breeding season. At such times 

 they are always busy hunting food, and go and come constantly, and they may 

 often be seen hovering suspended in the air like the Sparrow Hawk, locating their 

 prey or darting down noiselessly and swiftly, and grasping it with their talons 

 without arresting their flight an instant. The actual amount of food a pair of 

 these birds require to bring up their numerous family, generally averaging eight 

 or nine, is something enormous. Each Owl will eat fully its own weight in twenty- 

 four hours, if it can get it. 



Dr. Fisher (1893b) says that "of 32 stomachs examined, 3 contained 

 small mammals; 3, lizards; 3, scorpions; 1, a centipede; 30, insects; 

 and 1 was empty." In his table of stomach contents, he records 

 seven stomachs that contained between 40 and 60 locusts and other 

 insects each, and he says that "this little Owl will chase and devour 

 grasshoppers until its stomach is distended to the utmost." 



Next in importance come the mammals, including mice, rats, and 

 ground squirrels of various species, young prairie dogs, young cotton- 



