PASADENA SCREECH OWL 281 



Its habits are doubtless similar to those of the neighboring races. 

 The measurements of 10 eggs average 37.3 by 31.2 millimeters; the 

 eggs showing the four extremes measure 39 by 31.3, 38 by 32.5, 35.6 

 by 31.3, and 37.2 by 29.7 millimeters. 



OTUS ASIO QUERCINUS Grinnell 



pasadena screech owl 

 Plate 67 



HABITS 



According to the 1931 Check-List this race occurs in "southern 

 California west of the desert region and along the western flank of 

 the Sierra Nevada north to Mt. Shasta; also on the Pacific side of 

 northern Lower California north of lat. 30°30'." 



Dr. Joseph Grinnell (1915), in describing and naming it, says: 

 "Characters in general like Otus asio bendirei; differs in paler colora- 

 tion: Light drab or ashy rather than hazel tones prevail dorsally, 

 while beneath the black markings are sharper in outline, with very 

 little or none of the ferruginous marginings. The restriction or 

 absence of ferruginous on the chest, around the facial rim, and on the 

 ear-tufts, is a good character." 



Nesting. — There is apparently nothing in the nesting habits of this 

 race that calls for special comment, as they are similar to those of other 

 races. But an unusual nesting site is thus described by John McB. 

 Robertson (1925): "April 29, 1923, I discovered a nest in a bark- 

 filled crotch of a large eucalyptus tree beside our driveway, and only 

 about twelve feet from the ground. The nest was well concealed by 

 several years' accumulation of bark and trash and when discovered 

 contained one adult bird and three partly feathered young." 



Eggs.— The Pasadena screech owl lays ordinarily four or five eggs, 

 sometimes only three, and perhaps rarely six. These are indistin- 

 guishable from other screech owls' eggs of similar size. The measure- 

 ments of 46 eggs averages 35.4 by 30.2 millimeters; the eggs showing 

 the four extremes measure 38.2 by 30.2, 35.8 by 31.8, 32.4 by 30.3, 

 and 34 by 27.1 millimeters. 



Young. — E. Lowell Sumner, Jr. (1928 and 1929) has made some 

 extensive studies of the development of young Pasadena screech owls 

 and has published two papers on the subject, to which the reader is 

 referred. The progress of their growth is not materially different 

 from that of the eastern screech owl, which has been quite fully ex- 

 plained under that race. He says, however: "In closing, two fea- 

 tures seem to deserve special mention. One is the fact that after 

 the eggs had first begun to pip, more than three days elapsed before 



13751—38 19 



