THE ROCKY MOUNTAIN SCREECH OWL. 367 



the trees for the balance of the summer; but when the cold winds strip the 

 leaves from the trees in the fall suitable tree holes are selected for then- 

 winter quarters. 



"While stationed at Fort Custer, Montana, during the winter of 1884-'85, . 

 I took five of these birds, but was unable to find their nests. I discovered 

 their presence there quite accidentally. On December 1, 1884, while out 

 hunting Sharp-tailed Grouse in a bend of the Big Horn River, a few miles 

 south of the post, as I was walking by a thick clump of willows I indistinctly 

 uoticed a whitish looking object dropping on the ground, apparently out of 

 the densest portion of the thicket and on the opposite side from where I was 

 standing at the time, and simultaneously heard several plaintive squeaks from 

 that direction. Carefully skirting around the thicket, which was some 20 yards 

 long and perhaps 5 yards wide. I saw the object of my search savagely engaged 

 in killing a meadow mouse which it had just captured. I promptly shot it It 

 proved to be a female and excessively fat; in fact all the specimens I secured 

 subsequently showed conclusively that they managed to secure an abundance 

 of food in that Arctic winter climate, and that a portion of this at least seems 

 to be obtained in the daytime. The four other specimens collected by me were 

 all obtained in similar locations. I have no doubt that it breeds in the vicinity 

 of Fort Custer, but I lost trace of these birds in the spring months and failed 

 to hear their love notes at that time. It is possible that they- retire a little 

 nearer to the mountains to breed. This is, up to date, the most northerly local- 

 ity recorded at which the Rocky Mountain Screech Owl has been obtained." 1 



In Colorado full sets of eggs are sometimes found by April 1, and again 

 as late as May "25, the latter probably a second laying, the first having been 

 lt->t roved. But a single brood is raised in a season. Hollow cottonwood 

 trees furnish their favorite nesting sites, at distances from 4 to 25 feet from 

 the ground, but according to Mr. Gale they also breed at times in natural 

 cavities in box elders and black willows, and occasionally a pair will make 

 use of the adandoned nest of the Black-billed Magpie, as Mr. Anthony sur- 

 mised. Mr. William G. Smith, of Loveland, Colorado, has since informed me 

 that he found a set of eggs in such a situation in the spring of 1890. He 

 also states that remains of young cotton-tail rabbits are conspicuous near their 

 nesting sites while rearing their broods. He has found them nesting in the 

 timber along the creek bottoms, fully 20 miles out on the plains, away from 

 the foothills, and they probably reach points still farther east of the mountains. 



The eggs of the Rockv Mountain Screech Owl are pure white in color 

 and moderately glossy: the shell is smooth and finely granulated. In shape 

 they vary from oval to a broad elliptical oval, some being decidedly more 

 elongated than any other eggs of the genus Megascops I have seen. The usual 

 number of eggs to a set is four. Of ten sets taken by Mr. Gale, three con- 

 tained three eggs each, six contained four, and one set five eggs. They are 

 usually deposited at intervals of a couple of days, and incubation sometimes 

 begins with the first egg laid 



' Auk, Vol. vi, 1889, Ho. 4, pp. 29&-302. 



