Family	WESTERN GULL. [Western Gull.]
Genus	LARUS OCCIDENTALIS, Aud. [Larus occidentalis.]

Two specimens of this Gull have been sent to me by Mr. TOWNSEND. One of them an adult, is marked, "Male, Cape Disappointment, October 7th, 1836;" the other, a young bird, "Young Male, Cape Disappointment, October 6th, 1836." The iris of both is stated to have been light hazel. This species, which I presume to be undescribed, as I have not met with any account of it, is about equal to Larus marinus in size, and resembles L. argentatus in colour, but differs from both in many respects, as will be seen from the annexed description. It is especially remarkable for the great depth and comparative shortness of its bill, which in this respect approaches to L. melanoleucus of New South Wales. The adult specimen unfortunately has the wings imperfect, the primary quills having been only partially developed; but the wings of the younger bird are complete.

WESTERN GULL, Larus occidentalis, Aud. Orn. Biog., vol. v. p. 320.

Male, 27, wing 17 1/4, but the feathers not complete.


Adult Male.

Bill shorter than the head, robust, compressed. Upper mandible with the dorsal line straight as far as the end of the nostrils, decurved toward the end, the ridge convex, gradually narrowed to the point, the sides nearly flat, the edges sharp, inflected, toward the end direct and arcuato-declinate, the tip rather sharp; lower mandible with the angle long and narrow, the outline of the crura slightly arched, the dorsal line beyond the prominence at the angle ascending and slightly concave, the sides erect and nearly flat, the edges sharp, inflected, decurved toward the narrow tip. Nostrils medial, lateral, linear-oblong, wider anteriorly, in the fore part of the nasal groove, which is rather long and narrow.

Head large, broadly ovate, narrowed anteriorly. Neck of moderate length, thick. Feet of moderate length, rather slender; tibia bare for an inch and a quarter, reticulate; tarsus rather short, somewhat compressed, covered anteriorly with numerous scutella, laterally with angular scales, behind with numerous small somewhat rectangular scales. Hind toe very small and elevated; the fore toes rather long, the fourth little shorter than the third; all scutellate above, and connected by reticulate webs; the lateral toes margined externally with a thick membrane. Claws small, slightly arched, somewhat compressed, blunt, that of the middle toe with the inner margin expanded.

The plumage is full, close, elastic, very soft and blended, on the back and wings rather compact. Wings very long, broad (four outer primaries only partially developed); secondaries broad and narrowly rounded. Tail even (not fully developed).

Bill yellow, with an orange-red patch toward the end of the lower mandible. "Iris light hazel." Feet flesh-coloured, claws dusky. The head, neck, lower parts, rump, and tail, are pure white; the back and wings light greyish-blue, of a deeper tint than in L. argentatus; the edges of the wing and the extremities of all the quills are white; the first seven quills are greyish-black toward the end, that colour including the outer webs and the greater part of the inner of the two first, and on the rest gradually diminishing, so as on the seventh merely to form a subterminal bar; the first quill with a patch of white on both webs near the end; the tips of all being white.

Length to end of tail 25 inches (but the tail is not full grown); bill along the ridge 2 7/12, along the edge of lower mandible 3 1/4, its depth at the base 11/12 at the angle 11/12; tarsus 2 10/12; hind toe (3 1/2)/12, its claw (2 1/2)/12; second toe 1 9/12, its claw 5/12; third toe 2 6/12, its claw (5 1/2)/12; fourth toe 2 (4 1/2)/12, its claw 3/12.


Young Male.

Bill flesh-coloured, beyond the nostrils and angle black, with the tips horn-coloured. Feet flesh-coloured; claws brownish-black. The upper part and sides of the head, the hind part and sides of the neck light brownish-grey, mottled and streaked with white; on the back the colour is light greyish-blue, some of the feathers mottled with brown, the adult plumage having been partially assumed; the wing-coverts are chiefly of a greyish-brown colour; the primary quills greyish-black, without white at the end; the secondary blackish-grey, margined and tipped with white, finely undulated with brown. The rump is white; the tail greyish-black, tipped with white; the whole outer web of the outer, and the basal half of that of the next feather white; the lower wing-coverts dusky-grey. All the lower parts are greyish-white, obscurely mottled with pale brownish-grey.

Length to end of tail 27 inches; bill along the ridge 2 1/2, along the edge of lower mandible 3 2/12, its height at the base 10/12, at the angle 11/12; wing from flexure 17 1/4; tail 7 1/4; tarsus 2 11/12; middle toe 2 1/2, its claw (7 1/2)/12.

From the above description, it will be seen that in proportions and colouring this species does not differ much from L. argentatus. It is much larger, however; its bill is deeper and stronger in a very conspicuous degree, and its tarsi and toes are considerably longer.