Page:The birds of America, volume 7.djvu/162

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118
THE BLACK TERN.


Adult, 9, 24. Young, in autumn, 7§; wing, 9 T 8 2.

Arrives in Texas from the south early in spring, proceeds along the coast to the Mississippi, then ascends that river and its tributaries, breeding around ponds, or along the streams; and even advances to the Fur Countries, where it also breeds. Abundant. Migratory. Occasionally along the coasts of the Middle Atlantic Districts.

Adult Male.

Bill about the same length as the head, slender, tapering, compressed, nearly straight, very acute. Upper mandible with the dorsal line slightly arched, the ridge convex at the base, narrowed towards the end, the sides sloping at the base, slightly convex and nearly perpendicular towards the tip, the edges sharp, the tip acute. Nasal groove reaching nearly to the middle of the mandible; nostrils basal, linear, direct, pervious. Lower mandible with the angle very narrow, acute, extending beyond the middle, the dorsal line straight, the sides erect and slightly convex, the edges sharp and slightly inflected, the tip extremely acute.

Head of moderate size, oblong; neck rather short; body slender. Feet small; tibia bare for a short space; tarsus very short, covered anteriorly with small scutella, laterally and behind with reticular scales; toes very slender, the first extremely small, the third longest, the fourth nearly as long, the second much shorter, all scutellate above, the anterior connected by short reticulate webs, having a concave margin, and not extending much beyond the middle of the toes. Claws long, slender, arched, compressed, acute, that of hind toe smallest, of middle toe largest, and having a thin dilated inner edge.

Plumage soft, close, blended, on the head short, on the back somewhat compact. Wings very long, narrow and pointed; primary quills tapering, the outer slightly curved inwards at the end, the first longest, the rest rapidly graduated; secondary short, broad, incurved, rounded. Tail of moderate length, emarginate, of twelve rounded feathers.

Bill brownish-black. Iris brown. Feet reddish-brown, claws black. Head, neck, breast, sides and abdomen, greyish-black; lower tail-coverts white, lower wing-coverts bluish-grey. The general colour of the upper parts is dark bluish-grey; the outer web of the first quill greyish-black. Length to end of tail 9 inches, to end of wings 11; extent of wings 24; wing from flexure 8|; tail 3^-; bill along the back lj^, along the edge of lower mandible 1 T S 2-; tarsus T 8 2-; middle toe j, its claw -f-f . Weight 3 oz. Young Male in autumn.

The bill, iris, and feet, nearly as in the adult. The upper parts are grey- ish-blue, the feathers of the fore part of the back, and especially the scapu- lars, brown towards the end; the upper and hind part of the head greyish-