DESCRIPTION AND TECHNICAL OBSERVATIONS.
Genus Larus. Linn. Syst. Nat. I. p. 224, (1766.) Larus Heermanni. Cassin. Proc. Acad. Nat. Sci., Philada., Vol. VI. p. 187, (1852.)
Form. Bill rather long and slender; wings very long, extending beyond the end of the tail; first primary longest; tail truncate or slightly emarginate.
Dimensions. Adult. Total length of skin from tip of the bill to the end of the tail, about 17½ inches; wing, 13½; tail, 5½; bill from the angle of the mouth to the tip of the upper mandible 2½ inches.
Colors. Adult. Bill red, both mandibles tipped with black; feet and legs dark; head white, which color gradually blends into an ashy lead color enveloping the entire body above and below—darker on the back and wings and paler on the abdomen. Secondary quills tipped with white, forming an oblique bar when the wings are folded. Superior coverts of the tail very pale cinereous, nearly white. Quills and tail feathers brownish black, all of the latter narrowly tipped with white. Shafts of the two first primaries white on the inferior surface of the wing.
Young. Smaller, total length about 16 inches, wing 13, tail 5 inches. Entire plumage brown, darker on the head and paler on the under surface of the body; quills and tail feathers brownish black, the latter narrowly tipped with white.
Hab. Coast of California. Spec. in Mus. Acad. Philada.
Obs. We are acquainted with no species of Gull which intimately resembles the bird now described. Judging from the only description extant of Larus Belcheri. Vigors, which is in the Zoological Journal, Vol. IV. p. 358, and which is too short to be of service in this family of birds—it appears to resemble that species to some extent. L. Belcheri is much larger, and is described as having the entire plumage brownish lead-color, and as being 21 inches in total length. It appears to be, however, the only western American species with which our present bird can be confounded.
Plate 6
The Northern Sea Eagle
Haliaëtus pelagicus (Pallas)