Sept., 1907 SOME COLORADO NOTES ON ROCKY MOUNTAIN SCREECH OWL 143 



sheltered. The eggs are usually laid on a bed of refuse, such as wood dust and 

 the accumulations of a like nature (which are sure to be found in a tree cavity) 

 over which a thin layer of feathers of small birds has accumulated thru the feeding 

 of the owls, but I do not think that any attempt is made by the birds at nest build- 

 ing. The nests are always littered with the remains of small creatures — the food 

 of the brooding female— including frogs, craw-fish, small birds and rodents, and 

 occasionally a rabbit. The blood-stained eggs bear mute witness of the bloody 

 nature of the birds' feasts. 



The height of the cavities above the ground varies from five to forty feet, but 

 the majority are between ten and twenty feet. The average height of twenty-five 

 nests examined by the writer is 13)^ feet. Extremely high holes are rarely if ever 

 used by the birds. 



The great majority of full clutches contain four eggs, tho occasionally three or 

 five are deposited. In the twenty-five sets it has been my good fortune to examine 

 in the nests, the following sets were found: One of 2, five of 3, fifteen of 4, two of 



YOUNG OF ROCKY MOUNTAIN SCREECH OWL NOT YET ABLE TO FLY 



5, one of 6 and one of 7. The set of 2 was a second clutch, the first set of 4 hav- 

 ing been taken 23 days previously to the date upon which the set of 2 was found in 

 which incubation was about a fourth advanced. The comparatively large number 

 of sets of three conveys a wrong impression, and is probably due to a little over- 

 anxiety to collect the eggs, not giving the parent sufficient time to complete the 

 clutch. I believe one in fifteen sets would be nearer the proper ratio of sets of 3 

 and 4. The set of 6 was laid by a particularly^ prolific female which had laid sets 

 of five on the two preceding years; while the set of seven I cannot account for 

 unless it was laid by two females, which is very improbable. This set was found 

 May 30th, two birds were flushed from the cavity, and all seven eggs were addled. 

 These two last mentioned sets and one set of six collected by Prof. A. H. Felger, 

 are, so far as I can learn, the largest sets of this sub-species on record. 



Quoting from Bendire, "The eggs of the Rocky Mountain Screech Owl are 

 pure white in color and moderately glossy, the shell is smooth and finely granu- 

 lated. In shape they vary from oval to a broad elliptical oval, some being de- 



