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 Sept., i9o7 SOME COLORADO NOTES ON ROCKY M)UNTAIN SCREECH OWL I43 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 ful] clutches contain four eggs, tho occasionally three or five are deposited. In the twenty-five sets it has been my good fortune to exmnine in the n6sts, 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 inlpression, 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-