MEXICAN SCREECH OWL 275 



The measurements of 37 eggs average 34.3 by 28.8 millimeters; the 

 eggs showing the four extremes measure 35.5 by 29, 34.9 by 29.9, 32 

 by 28.8, and 34.1 by 24.1 millimeters. 



Plumages. — This screech owl seems to be wholly monochromatic, as 

 nothing approaching a gray or a brown phase has yet been discovered, 

 the universal color being pale, ashy gray. 



Foo'd. — Mrs. Florence M. Bailey (1928) lists, as the food of the 

 Mexican screech owl, "kangaroo rats, gophers, mice, rats, small birds, 

 frogs, lizards, snakes, crawfish, scorpions, grasshoppers, locusts, and 

 beetles. It is one of the most insectivorous of our owls." 



Behavior. — Henry W. Henshaw (1875) writes: 



This bird was very common both in Arizona and New Mexico, and is, I think, 

 the most numerous of the family in this region. Whenever our camp chanced to 

 be made near one of the groves of oaks, which are numerous, these owls were sure 

 to be heard soon after dusk, and, not infrequently, several would take up their 

 stations in a tree within a few feet of the camp fire, and remain for an hour or 

 more, apparently to satisfy their curiosity, uttering, from time to time, their low, 

 responsive cries. Their notes vary much in length, but, when full, consist of two 

 prolonged syllables, with quite an interval between, followed by a rapid utterance 

 of six or seven notes, which, at the end, are run together. They are very sociable 

 in their disposition, and, as soon as it is fairly dusk, the first call of a solitary bird 

 may be heard issuing from some thicket, where it has remained in concealment 

 during the day. After one or two repetitions, this will be answered by another, 

 perhaps half a mile away, and soon by a third and a fourth, apparently all coming 

 together; and I have heard at least eight of these owls, congregated within a short 

 distance in the tree tops. When the band was complete, they would move off, 

 still apparently keeping together, till their notes were lost in the distance. 



Enemies.— Mrs. C. J. Whitfield (1934), of Globe, Ariz., tells the 

 following interesting story: 



A heavy flapping of wings attracted our attention to an Arizona oak tree (Quer- 

 cus arizonica) about five yards from the house. Approximately 12 feet from the 

 ground, and quite close to the trunk, a snake over three feet long (probably 

 Pituophis catenifer rutihis) hung suspended by its tail from a small dead limb. The 

 large part of the snake's body was coiled once around a small owl, judged from its 

 color and size to be a screech owl (Otus asio cineraceus) . The bird struggled more 

 and more feebly for three or four minutes, and finally was still. 



When we shot the snake, its body grew slack, and its tail loosened its hold on 

 the limb and began to slip. The owl freed itself and flew away, seemingly un- 

 injured. The owl had apparently been roosting in the tree, and was "stalked" and 

 caught by the snake. 



OTUS ASIO AIKENI (Brewster) 

 AIKEN'S SCREECH OWL 



HABITS 



The A. O. U. Check-List (1931) gives the range of this subspecies 

 as "foothills and plains of eastern Colorado and Kansas north to 

 northeastern North Dakota and northwestern Minnesota and south 



