15. LARUS. 2f)3 



Conti: N. H. Alaska, p. 125 (1886); Riclyw. Man. N. Aynei: B. 

 p. 26 (1887) ; Kelson, Rep. B. Alaska, p. 51 (1887) ; F. M. 

 Chapman, Auk, If^QS, p. 393; Taczan. Mem. Acad. St. Petersb. (7) 

 xxxix. p. 1019 (1893 : E. Siberia). 

 Larus glaucescens, Taczan. Mem. Acad. St. Petersb. (7) xxxix. 

 p. 1019(1893: E. Siberia). 



Adult male in breeding-plumage. Head, neck, tail, and under- 

 parts white ; mantle pale pearl-gre}', the scapulars and secondaries 

 distinctly white at the tips ; primaries pale pearl-grey basally and 

 on the outermost webs, white terminally : bill yellow, orange-red at 

 the angle ; iris straw-yellow, orbital ring orange ; tarsi and toes 

 bright flesh-pink (in life). Total length about 29 inches, culmen 

 2-6, wing 18 to 18-5, tail 7"25 to 7"5, tarsus 2-7, middle toe with 

 claw 2* 7. 



The female is smaller, often considerably so ; but there is also 

 much individual difference in size, irrespective of sex. 



Adult in winter. Similar, but mottled and streaked with pale 

 brown on the head and neck ; while in birds which have bred for 

 the first time in the previous summer there is often a considerable 

 amount of pale brown mottling on the mantle also, until February 

 or even March. 



Young. Both upper and under surfaces streaked and mottled with 

 ash-brown on a paler ground-colour ; the feathers of the mantle 

 margined with buffish white, which produces a creamy appearance ; 

 outer quills clay-brown on their outer webs and paler on the inner 

 webs ; upper and under tail-coverts rather boldly marked with brown ; 

 rectrices, on the contrary, rather finely mottled : bill ochre-yellow to 

 the angle, thence blackish to the tip ; tarsi and toes brownish. 



After the moult of the next year, both upper and under surfaces 

 are much lighter, and pale grey feathers begin to show on the mantle, 

 the outer primaries being all but white. 



Immature. The mottlings of the upper surface gradually dis- 

 appear, and for a short time the bird appears to be creamy white (in 

 which phase of plumage it has received the name of L. hutcJiinsi). 

 At the subsequent moult the pearl-grey mantle is assumed, but the 

 new tail-feathers show some faint brownish mottlings until the next 

 year. 



Nestling (Ifith July, 1875). Stone-grey, with a slight tinge of 

 yellowish buff below ; the head spotted with black, and the back 

 mottled with ash-brown. 



Hah. Entire Circumpolar regions in summer ; southwards in 

 winter to the basin of the Mediterranean, the Black Sea and the 

 northern part of the Caspian, Japan and California in the Pacific, 

 Bermuda, Florida, and Texas on the Atlantic side. 



a. Juv. St. Cornwall, winter (Vinffoe). Purchased. 



b. Juv. St. Torquav, winter. C. Coningham, Esq. 



[P.]. 



c. $ ad. sk. Spiu-n Head, Nov. Dr. H. B. Hewetson 



[P.-j. 



d. Juv. St. Orknev (BuUock). Purchased. 



