GULLS AND TERNS 



19 



of head, including' ear coverts, 

 straAV yellow, paler on throat; 

 chest, and sometimes breast and 

 belly, white, shading- into gray on 

 sides ; imder tail coverts, and 

 usually belly, graj^ ; feet black ; 

 tarsus light bluish. Length : 20- 

 23, wing 12.25, bill 1.1 1», longest 

 tail feathers 10.50-14..")(). 



Distrilnition. — Northern part 

 of northern hemisphere, breed- 

 ing in arctic regions ; south in 

 winter to Florida, Gulf of Mex- 

 ico, and California. Taken at 

 Monterey Bay by Mr. Loomis. 



Eggs. — Deposited in a depres- 

 sion in the mossy top of a knoll. 



Fig. 3'J. Long-tailed Jaeger. 



The long-tailed jaeger i.s so swift and graceful on the wing that 

 Mr. Nelson compares its flight to that of the swallow-tailed kite. 

 After chasing each other about or pursuing hapless gulls or terns, 

 the birds may often be seen sunning themselves on an elevation, 

 their white breasts pointing them out at a long distance. 



FAMILY •LAR1D2B. GULLS AND TERNS. 



Fig. -KJ. 



KEY TO GENERA. 



Bill deeper through angle of lower mandible than 

 through nostril. 



2. Hind toe wanting, or a mere rudiment. 



Rissa, p. in. 

 2'. Hind toe small but perfect. 



3. Tail square across end .... Larus, p. 20. 



3'. Tail deeply forked Xenia, p. 27. 



iiSi^^^'tTY r. Bill deeper through middle of nostril than through 



angle of lower mandibh^. 

 Fig. 41. 



2. Tail forked for more than one fifth its length (ex- 

 c('i)t sometinu's in S. r<isj)ia); outer feathei-s nar- 

 row and pointed. 

 3. Length of bill le.ss than three times its depth at 



base Gelochelidon. p. 27. 



3'. Length of bill more than tliree times its dejith 



at b.ise Sterna, j). 27. 



2'. Tail forked for .ibout one fifth its total length, 

 outer feathers wide and rounded at tips. 



Hydrochelidon, p. M. 



GENUS RISSA. 

 40a. Rissa tridactyla pollicaris liulgw. Pacific Kittiwake. 



Appearance gull-like ; hind toe minute, with or without a nail ; feet 



