Other Name.—Marsh Tern.
Description.—Size small; tail short, forked. Adults in summer: Head and underparts black, save under tail-coverts, which are white; upperparts gray; bill and feet red. Adults in winter and immature: White, with pearl-gray back and wings and dusky spots on head; bill and feet dusky. Length: 10 inches.
Range in Pennsylvania.—Irregular as a migrant throughout the Commonwealth; more frequently seen than other Terns about marshes and on small bodies of water; usually seen between April 25 and September 30. Though it is thus to be seen in midsummer irregularly, it is not known to nest in Pennsylvania at the present time.
Black Tern, Adult
The adult Black Tern, as it courses about a marsh or pond, is a beautiful, buoyant creature. Its flight is swallow-like. It is probable that this species nests occasionally along the Lake Erie shore, or at some of the larger lakes wherever there are marshy shores.
DOUBLE-CRESTED CORMORANT
Phalacrocorax auritus auritus (Lesson)
Other Name.—Shag.
Description.—Four toes all webbed together; bill long and strongly hooked at tip; tail stiff and moderately long; plumage thick and firm. Adults in breeding plumage: Glossy greenish black, save on back which is dark gray, each feather being margined with lighter gray; two filamentous tufts of black feathers on back of head; neck with thin sprinkling of silken white feathers during period of courtship; bill blackish, marked at base with dull yellow; sack under bill yellow; eyes bright green. Immature and adult in winter (the plumage usually seen in Pennsylvania): Without crests, and whole plumage brownish black, somewhat mottled beneath, and with light area on throat; eyes grayish green, not bright green. Length: About 30 inches.
Range in Pennsylvania.—A migrant found principally along the larger water-ways from about March 20 to May 10 and from September 15 to November 15. It is occasionally seen in winter when the water is free of ice.
Double-crested Cormorant, Breeding Plumage
Cormorants sit low in the water so that, while swimming, their tails do not show as field-marks, but their long necks, large heads, and the strongly hooked bills distinguish them at a considerable distance. In flight their wings beat regularly.
The bulky, wide-winged White Pelican (Pelecanus erythrorhynchos) is occasionally noted as a straggler in Pennsylvania. It is white, with black wing-tips, and is so noticeably equipped with long bill and throat-pouch that it can hardly be confused with any other species. Its four toes are all webbed together, as in the Double-crested Cormorant. Additional records of this species are desirable.