LAEID^, GULLS. GEN. 281-5. 313 



ordinary Califbruian bird is distinguished by the above particulars ; but connects 

 directly with argentatus by the North Pacific strain {L. borealis Braxdt ; Baied, 

 Trans. Chicago Acad, i, 324), and the Siberian bird {L. cachinnans Pall.; L. 

 argentatus var., Middexdorp, Schrenk). 



A'^ % Ring-billed Gull. Adult plumage precisely like that of the last species, 

 and its changes substantially the same ; bill ^/■ee;a'.sA-yollo\v, encircled with 

 a hlack hand near the end, usually complete, sometimes defective, the tip 

 and most of the cutting edges of the bill yellow ; in high condition, the 

 angle of the moutli and a small spot beside the black, red ; feel olivaceous, 

 o1)scured with dusky or bluish, and partly yellow; the webs bright chrome. 

 (Observe the coloration of the feet in this and in califoniicus, as compared 

 with argentatus.) Notaljly smaller than argentatus; length usually 18-20 

 inches ; extent about 48 ; wing aljout 15 ; bill under 2, and only about i deep 

 at the protuberance ; tarsus al^out 2, obviously longer than the middle 

 toe. N. Am., abundant and generally distributed. L. delawarensis Ord, 

 Guthrie's Geog. 2d Am. ed. ii, 319 ; Lawe. in Bd., 846 ; L. canus Nutt., ii, 

 299; L. zonor/ajnchus Eicii., F. B.-A. ii, 421; Nutt., ii, 300; Aud., vii, 



152, pi. 446. CouES, I. c. 302 delawarensis. 



'0> Var. CALiFOEXicus. Apparently larger than ordinary delawarensis, and sometimes 

 nearly equalling argentatus, averaging perhaps 22 inches ; bill about 2, the black 

 band probably never perfect, the red spot more obvious ; feet colored as in the last ; 

 tarsus 2^, yet not, or not obviously, longer than the middle toe and claw. In all the 

 adult birds observed, the white spot on the 1st primary had enlarged to occupy the 

 whole end of the feather for about 2 inches, while the subapical spot on the 2d was 

 large — a state I have not observed in typical delawarensis. Arctic and Western 

 America, abundant. Laavk., Ann. Lye. N. Y. 1854, 79, and in Bu., 846 ; Coues, 

 I. c. 300 (excl. syn.). (Type specimen examined.) 

 j-uCf American Mew Gull. Small; length 16-18 inches; extent about 40; 

 wing 13-14; bill 1^, slender, its depth hardly or not over ^ ; tarsus about 

 equal to the middle toe and claw, both about If-. Bill bluish-green, yellow- 

 tipped, without any red or black; feet dusky bluish-green, webs yellow. 

 Mantle considerably darker than in delawarensis. Arctic and Western N. 

 Am., in the interior and along the Pacific Coast to California; I am not 

 aware that it occurs on the Atlantic, or anywhere in the United States east 

 of the Rocky INIountaius ; Nuttall and Bonaparte seem to refer to the pre- 

 ceding species in giving this range. It will be seen at once to be different 

 from any of the foregoing : aud it appears to show constantly some slight 

 discrepancies from the European L. canus. L. canus (adult) and L. 

 brachyrJiyncJiUS (young — type specimen examined) Eich., F. B.-A. ii, 

 420, 422; Nutt., ii, 299, -301; Coues, I. c. 302; Rissa seiitentrionalis 

 (adult) and L. sucldeyi (young — types of both examined) Lawr., Ann. Lye. 

 N. Y. vi, 265, 264, and in Bd., 854, 848. canus var. brachyri-iynchus. 

 f f Feet black, stout, rough, with short tarsi and excised webs. {Pagoxjhila.) 



^ I'O Ivory Gull. Adult plumage entirely pure white, the shafts of the 

 primaries yellow ; bill yellow, more or less extensively greenish or dusky 

 toward the base; feet black. Young: more or less spotted aud patched 



KEY TO N. A. BIRDS. 40 



