ANTHONY GREEN HERON. Butorides virescens anthonyi (Mearns)

Field characters.—Size small for a heron; length about 16 inches. Top of head greenish black; back and wings, grayish green; neck and shoulders, reddish brown; under surface chiefly grayish. Flight labored but direct; legs extending backward beyond tail. Voice: A moderately loud hoarse squawk; also clucking notes.

Occurrence.—Summer visitant in small numbers along Merced and Tuolumne rivers. Seen near Mountain King Mine, August 17, 1915, near Snelling, April 26, 1916, and 2 miles southwest of Lagrange, May 7, 1919. Frequents vicinity of sluggish water, perching on lower branches of overhanging willows; usually flies out over the water when changing position.

The Anthony Green Heron is to be met with only at low elevations and then chiefly along the slower moving streams and the ponds bordered by willows. Only three of the birds were actually seen by us, but the species is undoubtedly a regular summer visitant along the lower reaches of both the Merced and Tuolumne rivers. We have two records of birds seen from the windows of a moving train. Travelers en route to the Yosemite Valley are thus likely to catch sight of this heron while traversing the lower Merced cañon.

Our most intimate knowledge of the Anthony Green Heron was obtained on May 7, 1919, when a nest was discovered in a dense stand of willow and cottonwood trees on the bank of a slough near the Tuolumne River about 2 miles southwest of Lagrange. Great Blue and Night herons breed in colonies and place their bulky nests in plain sight in the tops of tall trees where the birds can command a wide range of vision. But the little Anthony Green Heron nests solitarily; it shows a marked preference for seclusion; it hides its nest in dense growths of willow or cottonwood, just beneath the green leafy crowns of these trees. The nest found by us was so located, about 25 feet above the ground in a slender willow, one of many that slanted toward the adjacent pond. The nest was supported on three twigs about 10 millimeters in diameter, which grew out on the under side of the trunk. The sitting bird had an almost clear view of the ground below, as there were but few bare dead branches beneath her, and practically no undergrowth. When disturbed, she flushed directly through the leaves above her head and made off over the nearby water.

The nest was of very loose construction, as are all herons' nests, a mere pile of dead brittle willow twigs from 1 to 5 millimeters in diameter and up to 400 millimeters in length. It measured 280 to 300 millimeters in outside diameter and about 180 millimeters in depth. In profile it was triangular, with the apex downward. There was a rounded depression in the top, 70 millimeters deep at the center, from which point it sloped up to the very rim of the nest. This depression held the 5 eggs, which were of the vivid unspotted green color common to eggs of most herons. Four of the eggs weighed 18.1, 19.3, 19.5, and 20.0 grams, respectively.

As the observer first approached, he could see, from below, the sitting bird; her dully streaked under tail coverts, her slender neck and bill, and her glistening eye showed plainly. When the observer started to climb the tree, she left the nest and, as she took off over the slough, he was able to see the cinnamon brown of her neck. The bird remained in the vicinity and her harsh squawk was heard twice at short intervals, followed in one instance by a series of clucking notes, such as one would give when urging a horse to start. This heron, like herons in general, gave little attention to cleanliness about the nest, and the ground and vegetation beneath the nest tree were spattered with white excrement, a telltale feature marking the location of the nest.