LARUS GLAUCESCENS, GLAUCOUS-WINGrD GULL. 623 



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N. A. lutrod. fig. of primaries (with labels of tbis and the accompanyinfi figure 

 transposed). — Dall & Banx., Tr. Chic. Acad. 1869, 304. — Finsch, Abb. Nat. iii, 

 1872, 83. 



Glaucus (jlauccscens, Brucii, J. f. O. 1853, 101. 



Laroides glancescens, Bhuch, J. f. O. 1855, 281. 



Leitcus glaucescens, Bp., Cousp. Av. ii, 185G, 216 ; Couipt. Rend, xlii, 1856, 770. 



Larus glaiicopterus, " Kittlitz." 



Glaucus gJdiicojjterus, Bhoch, J. f. O. 1853, 101. 



Laroides chalcopterus, BiiuCH, J. f. O. 1855, 282. 



Leticus chalcoptentti, Bp., Cousp. Av. i', 1856, 216 ; Com])t. Rend, xlii, 1856, 770. 



Larus chalco])terus, Lawk., B. N. A. 1858, 843. — Coues, Pr. Phila. Acad. 1862, 295. 



DiAO. L. pallio ca^nleO'perlaceo fere ut in L. argentato, priviarUs dorso concoloribus, apici- 

 bus statim nee sensim albis. 



(The shade of the mantle is idmost exactly as in argenlatus, and the primaries are 

 pictured exactly as in that species, the black of argenlatus beiug replaced by a pearly- 

 blue like the mantle.) 



Sp. Ch. — Bill long and rather weak, the upi^er mandible acute and projecting con- 

 siderably beyond tip of the under, the convexity near the end comparatively slight ; 

 angle pretty well defined, the outline between it and the tip about straight. First 

 primary longest ; the tarsus rather longer than the middle toe and claw. 



Adult iu summer. — Bill light yellow, an orange spot at the angle of the lower mandi- 

 ble, and a dusky one just above. Mandible pearl-blue, much the same shade as in 

 (D-geutatus. Primaries scarcely darker than the back, all with well-defined, rounded 

 apical spots of white. First, the base not appreciably lighter than the body of the 

 feather, with a well-defined white spot on both webs near the end, sepai-ated from the 

 white tip by a transverse band of the color of the body of the feather ; second, third, 

 and fourth, basal portions notably lighter than the terminal, fading into pure white at 

 their juncture with the latter, without spots except at the apex; fifth, sixth, basal i)or- 

 tions the color of the back, fading into white near the end, separated from the white 

 apices by a band, narrowest on the sixth, of the color of the outer primaries. Inner 

 primaries like the secondaries, with plain broadly white ends. Feet light liesh-color. 



Adult ht winter. — Head, neck, and breast thickly iiebulated with light grayish-dusky, 

 the throat mostly immaculate. 



Approaching ma(urit)/. — Bill dark-colored, yellowish along the culmen and gonys. 

 Wings and tail light grayish-ashy, the former Avithout sharply-defined white tips or 

 spots. Under parts generally marked with dusky, the wing coverts marked with 

 dusky and white. Feathers of the back narrowly edged with gray. 



lutermediate. — Bill flesh-colored, the terminal portion black. Wings and tail darker 

 than in the jireceding, especially on the outer webs of the former. Everywhere dusky- 

 gray, more or less mottled with white, the gull-blue of the upper parts appearing as 

 mottling of greater or less extent. 



Young-of-the-gear. — Bill black. Everywhere deep grayish-dusky, somewhat mottled 

 with whitish; the feathers of the back, wings, and upper tail coverts edged, tipped, 

 and crossed witli n»«re or less regular ti'ansverse bars of grayish-white. 



Nestling, nearly Jledged. — Dark gray; under parts, wings, and tail transversely waved 

 with rufous ; under parts nearly pure dark ashy-gray ; l)ill and feet black. 



Nestling, unjhdgtd. — Bill and feet black; head and neck dull whitish, irregularly 

 spotted w'v\\ blackish; upper parts spotted with grayish-black and grayish-white; 

 under [)arts more uniform gray, the abdomen fading into white. 



Dimensions. — Length, about 27 inches; wing, 16.75; bill above, 2.25; gape, 3.25; 

 height at angle, 0.70 ; tarsus, 2.60 ; middle toe and claw, 2.50. 



Hub. — Pacific coast of North America. 



The present is a well characterized species. The nu)st striking peculiarity of form 

 is in the bill, in the very slight comparative convexity of the culmen near the end, the 

 tip being slender and acute and projecting considcralily over the tip of the lower man- 

 dible. This form of bill is recognizable even in the young-of-the-year, in wliicli the 

 bill is every way ninch mualler than in the adult. The color of the upper parts is 

 much that of L. argiutatns. The terminal spots of the ])riniaries are ay well defined us 

 in the s])e(ieM with black |uiniaries, and are much and regularly rounded. The shafts of 

 the (piill- feathers are nuich the color of the webs. The dusky of the young birds is very 

 light, and, except iu the early stages, is much mottled with grayish-white. The upper 

 parts soon became very light-colored by the broad whitish margins of the feathers. 

 The primarit's early acquire notably lighter tips, but do not ()btaiu the well-<letined 

 white terininiil ai)e.\es, nor the spot on the first primaries, till maturity. The prima- 

 ries of the youngest birds have a shade of silvery-gray, which is quite peculiar, and very 

 dilfereut from the color of those i)arts in the young of (Iu- Gulls with black jiriuiaiies. 



Larux glauveneeuH may be considered a well-estaldislied species. .\s already noted, 

 it is when adult almost exactly like au argenlatus with tho black of the primaries re- 



