For reasons not well understood, they avoid particular districts during the breeding-season. Dr. Cooper has never noticed one, during this season, on the coast south of Santa Clara, has never seen one in the Colorado Valley, nor in the Sierra Nevada. At Visalia, where an extensive forest of oaks forms an oasis in the great Tulare plain, he met with large flocks of these birds, with the same gregarious habits as were observed on the coast. During the month of July, 1866, a large number of these Crows came every evening to roost in an alder-grove near the town of Santa Cruz. They gathered in long, continuous flocks from the neighboring fields, flying rather high. All at once they would descend, with zigzag turns, to the low trees, sportively chasing and pecking at one another, and chattering in the air. Mr. John K. Lord, who enjoyed an unusually good opportunity of comparing the habits of our common Crow with those of this species, has not the slightest doubt as to their distinctness, though so very like in all essential respects, as far as color, form of bill, and other details are concerned. The smaller size of this bird, the difference in voice, and their habit of building with mud a domed nest, sufficiently demonstrate their difference. This Crow he found principally near the sea-coast; retiring to the trees at high tide, following out its ebb and retreating before its flood, they feed on any marine food they can find. The caw of this species reminded him of the Jackdaws of Europe. During the breeding-season they abandoned the coast, from early May resorting by pairs to the interior. Selecting patches of open prairie, they build their nests in the bushes of the crab-apple or wild thorn, and something in the manner of the Magpie, arching over the top with sticks, with two openings for entrance and exit on either side. The inside is plastered with mud, and lined with a few loose grass-stalks. The eggs he found generally small, and of a lighter color than those of the common Crow. After nesting, they return with their young to the sea-coast, and remain in large flocks. During the breeding-season they feed on small reptiles, freshwater mollusks, insects, grubs, etc. Mr. Lord noticed them capturing butterflies flying near their nests. Their eggs range in number from five to seven. An egg of this species from Sitka measures 1.62 inches in length by 1.12 in breadth. It is of an oblong-oval shape, pointed at one end. The ground-color is a light sea-green, with marks and blotches of olive-brown, of varying size and different shades. Corvus ossifragus, WILSON. FISH CROW.