BLACK TERN. 537 



Sterna nigra, Linn. Syst. Nat. vol. i. p. 227 — Lath. Ind. Ornith. vol. ii. p. 810 — 

 Ch. Bonaparte, Synopsis of Birds of the United States, p. 355. 



Short-tailed Tern, Sterna plumbea, Wils. Amer. Ornith. vol. vi. p. 83. pi. 60. 

 fig. 3. Young. 



Sterna ni&ra, Black Tern, Swains, and Richards, Fauna Bor. Amer. part ii. p. 415. 



Black Teen, or Stern, Nuttall, Manual, vol. ii. p. 282. 



Adult Male. Plate CCLXXX. Fig. 1. 



Bill about the same length as the head, slender, tapering, compressed, 

 nearly straight, very acute. Upper mandible with the dorsal line shghtly 

 arched, the ridge convex at the base, narrowed towards the end, the sides 

 sloping at the base, shghtly 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 an- 

 teriorly 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 ex- 

 tending 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 some- 

 what 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 l^j, along the 

 edge of lower mandible 1/j ; tai'sus /j ; middle toe -f^, its claw ^*|. 

 Weight 3 oz. 



