LARID.E — THE GULLS AND TERNS — LARUS. 



243 



^ 



equal quantities, with brownish slate and grayish buffy white, the hitter bordering the feathers, and 

 forming broad irregular bars, mostly beneath the surface ; primary coverts, remiges, and rectrices 

 dusky black, the inner primaries more gray- 

 ish, the primary-coverts narrowly tipped 

 with white and the outer tail-feathers with 

 irregular broken bars of the same. Head, 

 neck, and lower parts mottled or clouded 

 with grayish white and brownish gray, the 

 latter prevailing on the head and neck — 

 nearly uniform on the nape. Bill dusky, 

 black at the tip and brownish basally ; iris 

 brown ; legs and feet brownish (in the dried 

 skin). Downy young ; Grayish white, purer 

 white centrally beneath, where immaculate ; 

 head marked by irregular dusky black spots, 

 of indefinite arrangement, but most numerous 

 above ; upper parts clouded with dusky gray- 

 ish. Bill black, tipped with pale yellowish 

 brown. 



Total length, 21.50 to 2.3.00 inches; *"*^^^H 



extent, 51.00 to 55.00 inches; wing, 15.00- 

 16.75 (average, 15.54); culmen, 1.G5-2.I5 



(1.83) ; depth of bill through angle, .60-.75 (.04) ; tarsus, 2.00-2.GO (2.25) ; middle toe, 1.70- 

 1.95 (1.88). [Fifteen adults.] 



The salient points distinguishing this well-marked species from others occurring in the same 

 regions consist in the peculiar shade of the mantle, which is a deep cinereous-blue, intermediate 

 between the plumbeous of oeeiil, atalis anil the pearl-blue of argentatus, and exactly as in L cochin- 

 nans, Pallas, of the Fahcarctic Region and 

 _ . ,^„ . — ^-^_ _ Northwestern America ; the red mandibular 



'^SsS ' ~ 7~ ' ~^*^ s l 10 ' "' anjentatus, etc., combined with a 



-**J5' \ - - - more or less complete black band near the 



r--J ~ T"" 2 ^ c '"'' "' 'h- e '''"> iLS '" ddawarensis, although 



\ ^ ..<.'. ^__ __— - * there is rarely, if ever, a complete band, as 



^\S~? in the latter species. The dark-brown irides 



and pea-green feet of the perfect adult dis- 

 tinguish it at once from all its allies, which, 

 except L. occidental is, 1 have, when adult, yellow or whitish irides and flesh-colored feet. 



As in other species of this group, the white picture? of the primaries increase in siz.e with the 

 age of the bird ; as coincident with this change, it may be mentioned that in the older individuals 

 the black spots of the bill are sometimes almost obsolete, being most distinct in younger specimens. 



This is an exclusively northwestern and northern species, and is found on the 

 Pacific coast in the winter ; but retires to its breeding-places in the summer. Mr. 

 Bernard Eoss claims to have met with it on the Mackenzie River. Dr. Cooper writes 

 that he found this Gull not rare on the Pacific coast in the neighborhood of San 

 Diego during the winter ; and he also states that it winters along the entire coast as 

 far north as Puget's Sound; but that it retires in the summer to its breeding-places 

 in more northern regions. He describes this species as being less vigorous in flight 

 than L. occidentalis, more inclined to dive for fish, and not so varied in its mode 

 of obtaining its subsistence. He thinks it probable that this species is one of those 

 Gulls which breed on Mono Lake and on other salt bodies of water in the interior 

 basin. 



1 L. occidentalis has brown irides, and yellow, though, according to the labels of some collectors, 

 flesh-colored feet ! 



