AMERICAN SPARROW HAWK. Falco sparverius sparverius Linnaeus

Field characters.—Our smallest hawk, only slightly larger than Robin, but appearing bigger because of the longer wings; wings pointed (pl. 44i) and, when closed, reaching nearly to end of tail. Two narrow vertical black stripes on side of head below eye; chin and belly white; top of head, back, and most of tail, rusty red; male with basal portions of wings slaty blue and tail with a broad subterminal black band and a white tip; female lacking slaty tone on wings, this being replaced by rusty brown, and tail narrowly barred with black throughout. Flight swift, with frequent quick turns; often hovers in one position for several seconds, with wings rapidly beating. Voice: A shrill kill-y, kill-y, kill-y.

Occurrence.—Common resident; most numerous in the San Joaquin Valley, but ranges clear up through the Hudsonian Zone, at least in summer; in Yosemite Valley, during most of year. Found chiefly about grass and meadow lands.

Most of our hawks are notably wary and difficult to approach, but the little American Sparrow Hawk may often be seen at a fairly close range. The traveler going into the mountains from the west will have good opportunities to observe this bird on the plains of the San Joaquin Valley, either from the windows of the railroad train or along any of the highways.

The sparrow hawk is decidedly misnamed, for it very rarely captures sparrows or other birds, but devotes its attention to small rodents, such as meadow mice, and to insects. Indeed we would be fully justified in renaming the bird, Grasshopper Hawk, so often are these insects eaten.

The sparrow hawk is to be seen at rest on a telephone pole or other conspicuous perch whence it can watch the surrounding country for the small game which constitutes its prey. Again it hunts over meadow and grassland, now darting along in rapid, sometimes erratic, flight; again hovering in one position for several seconds, its long pointed wings (pl. 44i) rapidly beating the air, while its keen eyes search the ground. Should prey of any sort be observed the bird darts down with surprising rapidity and seizes it. Occasionally, as where grasshoppers are abundant, this hawk is seen foraging on the ground much in the manner of a robin. Its shrill kill-y, kill-y is uttered at almost any time, both when the bird is resting and when on the wing.

During the nesting season a sparrow hawk will occasionally mount high into the air and then pitch down head foremost on set wings until close to the earth when it will change to a level course, or else hover, before indulging in further similar behavior.

At Dudley, east of Coulterville, on July 16, 1920, a family of nearly full-grown young was perched about on the branches of a dead pine, the young 'whinnying' whenever the parents came their way. In Yosemite Valley a nest was located high up in a rotted-out cavity of a black oak, north of the village.

Near Lagrange on December 23, 1915, a pair of sparrow hawks was seen pestering a shrike. Every time the latter put its head out of the thick bush in which it had sought safety, first one hawk and then the other would dart at it. Since the shrike could not be seen to have anything in its bill it could hardly have been attacked by the hawks on other grounds than as an object of prey. The hawks finally desisted and left the shrike in peace. Curiously, the same behavior was noted on the part of another pair of sparrow hawks and a shrike on the same day. It might be mentioned, also, that in two cases American Sparrow Hawks were seen pursuing the much larger Red-tailed Hawks, as if to drive the latter from the neighborhood.

The effective role of the sparrow hawk in checking the increase of certain kinds of animals and its consequent importance to farming interests, where these interests are dominant, is suggested by the contents of the digestive tract of a bird taken in Yosemite Valley on October 25, 1915. The dilated esophagus contained the heart, liver, and lungs of a meadow mouse (Microtus), while the greatly distended stomach held parts of a meadow mouse and of a shrew, a grasshopper, and 20 moth larvae averaging three-fourths of an inch long. As comprising one evening meal this mass of material certainly seemed adequate to last until morning!