Gen. Char. Head with a blended depressed moderate crest. Tarsus decidedly longer than middle toe, which is scarcely longer than the hind toe. Bill rather narrow; width at base about half the culmen. Tail broad, long, slightly forked; equal to the wings, which are moderately pointed, and reach to the middle of the tail. First primary shorter than the sixth.
This genus agrees with the preceding in the length of the broad tail, but
has a longer tarsus and a different style of coloration. The species are distinguished as follows:—
S. nigricans. Sooty black; abdomen and edge of outer web of lateral tail-feather pure white.
a. Lower tail-coverts pure white.
Greater wing-coverts paler toward tips of outer webs. Wing, 3.60; tail, 3.45. Hab. Pacific Province, United States, and Mexico … var. nigricans.
b. Lower tail-coverts blackish.
Greater coverts not appreciably paler at ends. Wing, 3.35; tail, 3.30. Hab. Middle America, north of Panama … var. aquaticus.[79]
Both rows of wing-coverts distinctly tipped with white; white edgings of secondaries very conspicuous. Wing, 3.35; tail, 3.30. Hab. New Granada; Venezuela … var. cinerascens.[80]
S. fuscus. Grayish-olive above, and on sides of breast; beneath (including throat) white, tinged with sulphur-yellow. Wing, 3.40; tail, 3.20. Hab. Eastern Province United States; Eastern Mexico.