100 YOSEMITE NATURE NOTES 



SCREECH OWL 



8-10 





HORNED OWL 



18-25 



^i 



JMi 



PYGMY OWL 







OWLS: Order Strigiformes 



HORNED OWLS, ETC.: 

 Family Strigidae 



SCREECH OWL (Otus asio): 8-10 

 in. Above gray, finely streaked with 

 black; below lighter, streaked and 

 barred with black; "ear" tufts at sides 

 of head, wanting in immature in sum- 

 mer; large yellow eyes. Song a low- 

 pitched whistle with notes near one 

 pitch; notes stacatto, beginning slowly, 

 accelerating, and dropping slightly in 

 pitch. Nests in tree cavities, often those 

 dug by large woodpeckers. 



Frequents oak woodland, broken co- 

 niferous forest, and willow and cotton- 

 wood stream-borders. R. below about 

 5,000 feet elevation in the western part 

 of the Vosemite region. Found in Yo- 

 semite Valley, especially among can- 

 yon live oaks. 



HORNED OWL (Bubo virgini- 

 anus): 18-25 in. Above mottled with 

 gray and brown; throat white; rest of 

 under parts with narrow wavy black 

 bars on whitish; horn-like "ear" tufts; 

 large yellow eyes. Voice a deep, reso- 

 nant, low-pitched ixhoo too-whoo iihoo 

 whoo, all essentially on one pitch. The 

 female has a higher pitched voice of 

 more variable pattern. 



R. in a variety of habitats from 

 wooded areas to desert cliflfs, occurring 

 from sea level to timberline. Widely 

 distributed in the Yosemite region, 

 largely below the Hudsonian life-zone 

 but occasionally in this zone. Obser\-ed 

 at Ten Lakes and at 10,700 feet on 

 the Lyell Fork. 



PYGMY OWL (Glaucidium gno- 

 ma): 7-7/2 in. Above dark, brownish- 

 gray with whitish spots, most abundant 

 on head; throat white; below white, 

 streaked with fine black lines; tail long 

 for owl, barred with white, projecting 

 back at angle when bird is perched; 

 no "ear" tufts; eyes yellow. Voice a slow 

 series of mellow whistled notes often 

 on one pitch, occasionally interrupted 



V^V 



