PACIFIC HORNED OWL. Bubo virginianus pacificus Cassin

Field characters.—Large size (length about 20 inches); ear tufts present and conspicuous (fig. 39e); exceeded in size only by Great Gray Owl, which lacks ear tufts. Plumage chiefly a mixture of dark and light brown, streaked on back and barred on under surface; eyes yellow. Voice: A deep, reverberant, deliberate, whoo, whoo-whoo, whoo, or too-whoo, whoo.

Occurrence.—Resident in moderate numbers throughout the region below Hudsonian Zone; observed in Hudsonian Zone once, at Ten Lakes. Lives in open woods in mountains, along wooded ravines in foothills, and in river-bottom timber in the lowlands.

The Pacific Horned Owl is the owl which ranges most widely through the Yosemite region. It is nowhere common, yet it is likely to be met with anywhere from the cottonwood groves along the Merced River at Snelling to the Jeffrey pine woods of the Canadian Zone. In the Hudsonian Zone we found it only at Ten Lakes; its general absence from the higher zones may be due to the lack there of appropriate food. On the east slope of the Sierras we found the species at Walker Lake.

Horned owls, wary birds more often heard than seen, usually will not permit of close approach. It seems probable that in detecting the presence of people they depend fully as much on hearing as on sight. At Lagrange, Mr. Dixon tried several times to get near a horned owl heard regularly on several successive evenings in a certain steep-sided, tree-clothed ravine. Keeping entirely out of sight he tried to approach behind a ledge of rimrock; but the owl, seeming to hear his footsteps, flushed while he was some distance away and still completely out of sight.

These owls begin to stir about at dusk and at that time are wont to take commanding positions on the bare tops of dead trees whence they can watch or listen for prey and detect the distant approach of enemies. Their activity extends throughout the night and until late dawn. Their deep-toned reverberant hooting is most often heard in the evening and morning twilight; but, as many a camper can testify, it may be uttered as well during the midnight hours. Heard out of doors during the middle of the night, their heavy voices leave an impression long retained. The time of their appearance varies with the season. At Lagrange in December they were out and hooting by 4:30 P.M., while in midsummer they were not to be heard until 7 o'clock or later. On dark days they were occasionally heard during the daytime. Usually, with the coming of dawn the birds seek shelter in tall dense-foliaged trees where they spend the day in quiet.

The Pacific Horned Owl has a reputation for feeding on poultry, particularly in outlying communities where the fowls are in the habit of roosting in the trees in the barnyard. Mr. George Smith, our packer, told us that in his experience a horned owl would not ordinarily pounce directly down on a sleeping hen, but "would alight on a limb where a number of chickens were roosting. Then it would crowd against the birds until the one on the opposite side was forced to fly," whereupon the owl would also take wing and catch its prey when the latter was in motion.

Mr. Donald D. McLean says that a horned owl taken 8 miles northeast of Coulterville was captured in a rabbit snare on the ground. At Aspen Valley we found the mummified remains of a horned owl impaled on a barbed wire fence. One wing was broken and literally wrapped around the middle wire of the fence. Evidently the owl had hit the fence while in flight and its struggles to get free had but fixed its feathers more firmly on the barbs of the wire.