MARSH HAWK. Circus hudsonius (Linnaeus)

Field characters.—Much smaller than Red-tailed Hawk, and with relatively longer and narrower tail and wings (pl. 44a); a white (rump) patch above base of tail. Adult male pale bluish gray above, whitish below; adult female, and immature of both sexes, dark brown above and paler brown, somewhat streaked, below. Flight slow, indirect, with deliberate wing beats and frequent skimming low over ground. Never circles like Red-tail.

Occurrence.—Resident at lower altitudes on west slope of Sierra Nevada and passes in migration east of mountains. Observed at Snelling and reported from Smith Creek east of Coulterville. Noted in Yosemite valley by us, May 16, 1919, and by Mr. Joseph Mailliard (1918, p. 18), September 26, 1917. Seen during fall months near Walker Lake and Williams Butte. Frequents vicinity of meadows and marshes.

The Marsh Hawk is to be looked for over large open pasture lands and marshes where it hunts, in its own special manner, for the small animals which live in the short vegetation. Over such territory it floats about with an appearance of laziness or indifference, slowly flapping its long wings a few times and then sailing. It often skims low over the meadows, but it never mounts high in the air to circle or soar like the Red-tailed Hawk. When on the wing the bird's white 'rump' patch gives an effect of its tail being disconnected from the body. The whole demeanor of the bird, totally unlike that of the active "bullet hawks" or speedy falcons, is one of deliberation.

In mid-September of 1915, near Williams Butte, we saw five Marsh Hawks harrying over a small meadow in search of grasshoppers. On another occasion one was seen perched on a post beside an alfalfa field. Meadow Mice, too, are known to constitute a staple article in the diet of this hawk.