LONG-EARED OWL. Asio wilsonianus (Lesson)

Field characters.—Size medium for an owl (somewhat larger than pigeon); head and face rounded, with two long ear tufts on top of head just above eyes (fig. 39d, pl. 42a); plumage chiefly dark and light brown, in fine complex pattern; eyes yellow. Voice: Of adults, a low, mellow, long-drawn-out hoot, uttered at varying intervals; also, of both adults and young, cat-like calls.

Occurrence.—Resident locally both east and west of the Sierra Nevada, below the Canadian Zone. Observed nesting commonly near Williams Butte, and once in Yosemite Valley. Lives in dense tree growths, preferably along or near streams, and forages over adjacent meadowlands.

The Long-eared Owl seems to be of very local occurrence in the Yosemite region. We found it only in Yosemite Valley and in the open country south of Williams Butte. It probably occurs in some numbers to the west ward also, along the lower reaches of the Merced and Tuolumne rivers; but we did not happen to see it there.

This owl differs from the other members of its family in the Yosemite region most especially in its choice of a nesting site. Most of our species of owls roost and nest in cavities in trees or in caves in rocks; but the Long-eared Owl finds shelter for itself and its nest in thickets of trees or shrubs on marshy lands or near streams. None of our owls is known to 'build' a nest in the accepted sense of the word; they all make use of some existing structure, be it a natural shelter or the nest of some other bird.

On the floor of Yosemite Valley at late dusk (8:00 and 7:35 P.M.) on the evenings of July 28 and 29, 1915, strange notes having a grating, tinny quality were heard repeatedly. On the morning of July 31, when the same sound was heard in the same locality, a close scrutiny of trees in the vicinity was undertaken, which disclosed the maker of these sounds to be a young Long-eared Owl, chiefly in the grayish down of the natal plumage. The owlet was perched about twenty feet up on a swaying branch of a young incense cedar standing in a dense thicket of the same sort of trees. The empty nest was close by, about thirty feet above the ground in a small yellow pine, and was partly supported by branches of a slender cedar which were interlaced with those of the pine. This was only about 200 feet from the Cooper Hawk's nest discovered a few days previously (see account of that species), and was probably an old nest of that hawk, for it was similarly constructed of coarse sticks. The nest was smeared with excrement, indicating that a brood of young had been reared in it recently. On the ground directly beneath the young bird there was a fresh, headless Yosemite Meadow Mouse (Microtus montanus yosemite) and many disgorged pellets, while the surrounding ground was splashed with white excrement.

When Mr. Dixon first arrived at the Farrington Ranch, near Williams Butte, on April 27, 1916, he found Long-eared Owls numerous there and already nesting. From that date on, he had excellent opportunity to study the birds as they incubated their eggs and reared their young. (See pl. 42.)

Seven nests or broods of the Long-eared Owl were found, and 3 of these were kept under intermittent observation during the months of May and June. In all cases the owls had preempted older nests of the Black-billed Magpie, a bird common in that vicinity. The owls begin to nest somewhat earlier than do the magpies, and hence gain possession of the last year's nests before the original builders have occasion to reclaim them. The magpies thus have to build anew. In almost every instance a newly constructed and occupied magpie's nest was found within 15 to 50 feet of an owl's nest.

The owls were rather easy to photograph, as the accompanying illustrations will indicate. If the sitting bird flushed at his approach it was only necessary for the observer to go away for a few minutes and the bird would return. Then a quiet approach would make it possible to set up the camera at a relatively short range. The owls usually gave little heed to the camera, save to glare at the lens as though the reflection seen there were another and intruding owl. One individual, thought to be a female, was more aggressive, and several times attacked the photographer openly. She would wait until Mr. Dixon put his head under the focusing cloth; then she would swoop down and strike his head. At first the bird used only her wings, but later, becoming emboldened, struck with her claws, and once inflicted slight wounds in his scalp.

In one instance the incubating bird remained on the nest until Mr. Dixon was but 6 feet away (pl. 42a). Then it flushed and began hooting, whereupon its mate appeared. Another time the sitting owl remained until the observer was but 5 feet away. Then she (the bird was thought to be the female) hopped to a drooping willow about 12 feet away, fluffed out her feathers, flapped her wings, hooted and then uttered a me-ow-ing call exactly like that of a house cat. This woke her mate, who previously had been sleeping in another willow thicket a few yards away. There then ensued a duet of calls which "sounded like a pair of angry tomcats." Both birds flew about the nest, but would neither alight on it nor quit the vicinity so long as the intruder remained.

Fig. 40. Pellets and bones picked up under nest of Long-eared Owl in Yosemite Valley, July 31, 1915. About 2/3 natural size. See text for analysis.

The hoot of the adult birds is low, mellow, and long-drawn-out, and bears a resemblance to the note of the Band-tailed Pigeon. With each note the throat expands and contracts but the bill is kept closed. The cat-like cries are accompanied by a spreading of the wings, and while uttering them the bird usually totters and struggles as though caught in a trap. When surprised on the nest the owls would raise their 'ears' (pl. 42a), but when they were left alone, or when perched elsewhere, the ear tufts would be flattened down on the head so as scarcely to be visible. Sometimes when excited they clicked their bills in the manner common to most species of owls. Later in the season, when the young were out of the nest, the adults would fluff up their feathers and strike their wings against their sides, producing a 'plopping' sound.

A nest seen on May 9 held 4 eggs in which incubation had begun. By June 2 this nest held 4 young owls which were being brooded by the female parent. Three were still in the natal down, but the fourth and largest one had begun to acquire the gray feathers of the juvenile plumage. When the nest was watched, both the parents attempted by the usual tactics to distract the intruder's attention. These methods failing, the female left the vicinity and did not return during the hour that Mr. Dixon spent at the nest.

This nest was again visited on June 22. By this time the young owls were out of the nest and in Shepherdia bushes about a hundred yards away. They had not yet learned to fly but were able to hop about readily. They uttered low whining notes when the parent birds came to feed them.

Another brood of young owls which was hatched about May 20 had disappeared ten days later. Either they had been blown out of the nest by the hard winds of the intervening days or, perhaps, they had fallen victims to the ever present magpies. The latter were always about the owl nests while the old owls were incubating, and it seemed as though the parent birds would have to guard their treasures vigilantly in order to prevent the magpies from destroying the eggs or young.

In one instance, after the young of a brood were partly grown, one of the owlets was picked up in the hand. At this the female parent, in the top of a 15-foot willow near by, let out an "agonized, blood-curdling squawk," and allowed herself to fall down through the thicket to the ground, where she fluttered with a well-feigned semblance of injury.

Upon summarizing the nesting data gained at Williams Butte, we find that of the 7 nests or broods examined 3 were of 5 eggs or young each, and 4 were of 4. All the nests were in willow or Shepherdia thickets. All sets of eggs were complete by May 1, one had hatched by May 6, and one had not hatched by May 17. The individual records follow:

No. 1.	April 27, 5 eggs; later deserted.
No. 2.	April 29, 5 eggs; later destroyed.
No. 3.	April 30, 4 eggs.
No. 4.	May 6, bird on 2 downy young and 2 pipped eggs.
No. 5.	May 9, 4 incubated eggs; June 2, 3 small young in down and 1 larger young one with flight feathers partly out; June 22, young out of nest and in thickets near by.
No. 6.	May 15, 4 young with ear tufts and wing quills beginning to grow out; May 18, about half-grown (pl. 42b); June 1, out of nest.
No. 7.	June 27, brood of 5, with both parents, encountered together in willow thicket.

Unlike the nest found in Yosemite Valley, all of those near Williams Butte were clean and almost altogether free of animal remains, so that little was to be learned concerning the food habits of the Long-eared Owls there. In one instance, a freshly killed White-footed Mouse (Peromyscus sp.) was found beneath an occupied nest.

The pellets from the Yosemite nest (fig. 40) upon examination proved to contain chiefly remains of the Yosemite Meadow Mouse. One long pellet contained practically the entire skeleton and hair of a mouse of this species, together with numerous feathers and bones of a Spurred Towhee. One pellet contained bones from the hinder portion of a Yosemite Pocket Gopher (Thomomys alpinus awahnee). The materials in all of the pellets were consolidated into surprisingly compact masses. Often the long bones of the rodent skeletons are thrust into the open parts of a skull; only rarely do they protrude from the surface of a pellet. The hair is felted down so that the whole mass has a smooth exterior, not likely to scratch the owl's gullet.

Hunting almost exclusively at night, this owl does not capture many birds. The Spurred Towhee here recorded as being captured is notable for being especially active at dusk, just when the Long-eared Owl begins its nightly forays. The Long-eared Owl, although roosting and nesting in dense thickets, does its foraging in the open, and small birds are not as available there, at least at night, as they are in the trees and bushes through which certain other species of owls, known to capture birds, are wont to hunt. The meadow mice and gophers are most active in the early hours of the night, when presumably this owl does most of its foraging.