Animal Life in the Yosemite
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THE BIRDS

CALIFORNIA PIGMY OWL. Glaucidium gnoma californicum Sclater

Field characters.—Size very small (smallest of our owls); total length only about 7 inches, expanse 14-1/2 inches; head round, without ear tufts (fig. 39a); eyes yellow. Color of plumage above grayish brown, relieved by small white spots; below white, with sharp blackish streaks. Voice: Different from that of any other owl, and frequently heard during the day; a single mellow whoot, repeated at intervals; or a prolonged slow trill, followed by two or three isolated whoots: too-too-too-too-too-too-too-too-too; whoot; whoot; whoot.

Occurrence.—Apparently a common permanent resident of the Transition Zone, and perhaps also of the upper margin of the Upper Sonoran Zone. Inhabits sparse woods. Definite stations: Yosemite Valley, 3900-4200 feet; El Portal, 2000-2500 feet; Smith Creek, on Coulterville Road, 2800 feet.

In Yosemite Valley, the voice of the California Pigmy Owl was heard more frequently than that of any other nocturnally active bird. The first indication of the presence of this owl was a regular concert beginning at early dark and lasting until dark, given on the evening of October 10, 1914, in the strip of pine, cedar, and fir woods between the road and the cliff-wall below LeConte Lodge. Two birds about 300 yards apart were answering one another, and at one time a third was heard in the distance. The calls consisted of a slow trill, rather mellow, but not so mellow nor of such full quality as in the call of the California Screech Owl—more like the slow roll of the flicker. This trill would continue some seconds, then came a pause, then one note, an equal pause, and a second note. In one instance a third note was added. The striking characteristic was the pause after the trill, followed by the two detached notes. Once three far-separated notes were heard, not preceded by any trill. The following syllables if uttered while one whistles, seem to represent the pigmy owls' usual song: too-too-too-too-too-too-too-too; toot; toot; toot.

On October 12 similar notes were heard at 6:30 A.M. in the same vicinity; and on October 14, at 9:30 A.M., others were heard from the dark shaded valley wall near Bridal Veil Falls.

During the summer and fall of 1915 the voice of the pigmy owl was heard practically every evening that observations were made, in the vicinity of Yosemite Falls Camp, and from there down to Rocky Point and across the Ahwahnee footbridge. On August 18 and 19 the notes were heard at daybreak; on September 2 at 5:30 A.M., in broad daylight, and again at 6:50 P.M.; on September 4 at daybreak; and on October 23 at 5:22 P.M. On October 24, near Camp Ahwahnee, three owls were heard, the earliest at 5:22 P.M. On the evening of October 25 the first note was heard at 5:21 P.M. On October 27 three owls were heard near Camp Yosemite from as many different directions, beginning at 5:30; they called persistently for about fifteen minutes, after which perfect quiet reigned. On November 1, a clear sunny day, the regular full series of notes was twice heard at 11 A.M.; and on November 3, a day partly overcast, the notes were heard at 12:20 P.M.

Near El Portal, on December 6, 1914, a pigmy owl was obtained through the assistance of solicitous song birds. A bevy of fully fifteen ruby-crowned kinglets was buzzing like bees about the foliage of a tree, each uttering its ratchet-like call, and flitting hither and thither in the most perturbed manner. While the observer was watching, a pair of plain titmouses joined the group, and soon there flew out a pigmy owl, quickly followed by a good part of the excited congregation.

On December 10, 1914, about 11 A. M., near LeConte Lodge, a creeper was heard squeaking emphatically, with its attention fixed on the lower branches of a yellow pine. Presently a pigmy owl disclosed its presence by taking flight. It alighted near by on a pine twig thirty feet above the ground, and there it was shot.

Subsequent dissection of this owl showed its stomach to contain one forefoot, some bones, and much hair of a Yosemite Pocket Gopher. The stomach of a California Pigmy Owl obtained at El Portal, December 26, 1914, contained fragments of a small snake and of several grasshoppers. This further betokens daytime foraging on the part of this, our smallest species of owl.



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Animal Life in the Yosemite
©1924, University of California Press
Museum of Vertebrate Zoology

grinnell/birds58.htm — 19-Jan-2006