286 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



Eggs. — Xantus's screech owl evidently lays two to four eggs. Mr. 

 Rowley took one set of four, two sets of three, and two sets of two. 

 They are like other screech owls' eggs but smaller than those of the 

 larger races. The measurements of 14 eggs average 34.2 by 29.3 

 millimeters; the eggs showing the four extremes measure 35 by 31 and 

 32 by 27 millimeters. 



Plumages. — Dr. Bishop tells me that xantusi has two color phases, 

 showing about the same degree of difference as exists in the two phases 

 of triehopsw, that the brown phase predominates, and that in this 

 phase the upper parts are "wood brown" or lighter; in the gray phase, 

 xantusi is the palest of the southwestern races, a trifle paler than 

 gilmani, and less heavily streaked above and below. 



OTUS TRICHOPSIS (Wagler) 



SPOTTED SCREECH OWL 



HABITS 



The spotted screech owl superficially resembles, in its gray phase, 

 the other screech owls in the region it inhabits, from the mountains 

 of southern Arizona southward through Mexico to Guatemala. But, 

 on close examination, it is readily seen to be a distinct species, and 

 not a subspecies of Otus asio. This species is decidedly dichromatic, 

 having very distinct gray and red phases, which is not true of any of 

 the southwestern races of Otus asio. 



Both phases are quite distinct even in the downy, juvenal plumages; 

 these and the two adult phases are fully described by Ridgway 

 (1914), but his account is too long to be quoted here. The most 

 conspicuous characters by which the species can be recognized are 

 the large white spots on the lower hindneck and on the scapulars 

 and greater wing coverts, the large black spots on the under parts, 

 and the greatly developed bristly tips to the feathers of the face. 



We are indebted to Edouard C. Jacot (1931), who for ten years 

 has braved the hardships and dangers of night work in the mountains 

 of southern Arizona studying the screech owls, for most of our 

 knowledge of the habits of these elusive birds. He says that "this 

 year fifty nights were spent in the field and some twenty square miles 

 of country were worked." Having spent some time with him in the 

 Huachuca Mountains in 1922, I can appreciate the difficulty of this 

 work. 



As to the range of the spotted screech owl, he says that it "is a 

 permanent resident in the Huachuca Mountains. * * * This is 

 evidently a bird of the Arizona white oak (Quercus arizonica) belt, 

 and none was taken outside of this region, all having been secured 

 between 5,500 and 6,500 feet elevations." 



Courtship. — Jacot gives the following interesting accoimt of the 

 mating calls of this owl: 



