LARIB^ — LABINM: GULLS. 



747 



lull 



IS, 



dusky; darkest on the latter; all with light edgings. Primaries uniform brownish-hlack, 

 without white spots, tips, or lighter bases. Tail almost entirely br(jwuisl-i- black, with a 

 nan-ow border of white. Young in August : Bill and legs as in the preceding. Ev(.Tyw!)pre 

 whitish-gray ; the white of the under parts appearing as mottling, and the blue of the upper 

 parts as irregular patches. Dimensions: length 17.50; extent 42.00; wing 13.75; 

 al)ovel.l0; gape 2.00; width at nostrils 0.25; height 0..35, height at angle 0.35; tar 

 and middle toe with claw, 1.80. Interior of Arctic America, and Pacific coast generally. X(jt 

 authenticated as oecurriug on the Atlantic coast. The American representative of L. canus. 

 781. L. heer'manni. (To Dr. A. L. Heermanu. Fig. 509.) White-he.\ded Gull. Very diflerent 

 from any of the foregoing, belonging to a different section of the genus {Blasqms). Bill sliorter 

 than head or tarsus, rather slender, moderately compressed, the tip rather acute; its color red in 

 part in the adult. Folded wings reaching beyond the tail. Tail of moderate length, even, shghtly 

 emarginate in the young. Feet rather large. Tarsus equal to the middle toe and claw, (gen- 

 eral colors dark ; tail mostly blackish. Adult, breeding plumage : Bill bright vermilion red, 

 black for its terminal third, sometimes wholly red ; a red ring around eye. Head white; this 

 color gradually merging on the neck into plumbeous-ash, which extends over the whole under 

 parts, being lighter on the abdomen and under tail-coverts than elsewhere. The back is deep 

 plumbeous-slate, ligliter on 

 the rump. Upper tail-cov- 

 erts clear ashy. Upper sur- 

 faces of wings like the back ; 

 the jirimaries black ; the tips 

 of all, except the two or 

 three outer ones, narrf)wly 

 white. Tail black, nar- 

 rowly tipped with white- 

 Legs and feet reddish-black. 

 Young-of-the-year : Smaller 



Fig. 609. 



(From Sclater and Salvin.) 



Wliite-headed Gull, § nat. size. 



than the adult. BiU and feet brownish-black. Entire plumage deep sooty or fuliginous- 

 blackish ; all the feathers, but especially those of the back and upper wing-coverts, edged 

 with grayish-white. Primaries and secondaries black, as in the adults, with only traces of 

 white tips on the former. Tail black, very narrowly tipped with dull white. Immature : 

 Bill as in the adult. Head all round, and the throat, mottled with brownish-black and dull 

 white, the latter color predominating on the forehead and throat. Upper tail-coverts lighter 

 than in the adult, and the white tips of the tail-feathers broader; otherwise generally as in the 

 adult, but with all the colors rather deeper. Dhnensions : " length about 17.50 ; wing 13.50 ; 

 tail 5.50"; length of skin 18.50; wing 14.00; tail 5.75; bill along culmenl.80; along gape 

 2.40; depth at base 0.55; at angle, about the same ; tarsus 2.20; middle toe and claw a little 

 less. Young: wing 12.25; tail 4.75; bill along culmen 1.00; depth at base 0.50; at angle 

 9.45 ; tarsus 1.90. Length of some skins up to about 20 inches. Pacific coast of N. Am., from 

 British Columbia to Guatemala ; singular among all our species in dark lead-color with white 

 head and red bill ; common on the California coast. 



BIS'SA. (Icelandic name, rissa or ritsa.) Kittiwakes. Bill stout, rather short, little com- 

 pressed at the base, shorter than the head, equal to middle toe without claw, longer than tarsus ; 

 tip decurved and attenuated ; convexity of cnlmen regular and gradual from base to tip ; gonys 

 concave, in consequence of the great deflection of the apex of lower mandible ; outline of rami 

 slightly concave; eminentia symphysis well marked and acute, but not large. Wings very 

 long, pointed, reaching beyond the tail ; the primaries pointed, first longest. Tail moderately 

 long, even or (in young) emarginate. Legs stout and short. Tarsus remarkably short, less 

 than middle too alone ; anterior toes all long, and united by broad, full webs with unincised mar- 



