GULLS AND TERNS 
19 
of head, including ear coverts, 
straw yellow, paler on throat; 
chest, and sometimes breast and 
belly, white, shading into gray on 
sides; under tail coverts, and 
usually belly, gray; feet black ; 
tarsus light bluish. Length : 20- 
23, wing 12.25, bill 1.19, longest 
tail feathers 10.50-14.50. 
Distribution. — 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. 39. Long-tailed Jaeger. 
The long-tailed jaeger is 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 LARIDJEj : GULLS AND TERNS. 
Fig. 40. 
KEY TO GENERA. 
1. Bill deeper through angle of lower mandible than 
through nostril. 
2. Hind toe wanting, or a mere rudiment. 
Rissa, p. 19. 
2'. Hind toe small but perfect. 
3. Tail square across end .... Larus, p. 20. 
3'. Tail deeply forked. Xema, p. 27. 
Fig. 41. 
1'. Bill deeper through middle of nostril than through 
angle of lower mandible. 
2. Tail forked for more than one fifth its length (ex¬ 
cept sometimes in S. caspia ); outer feathers nar¬ 
row and pointed. 
3. Length of bill less than three times its depth at 
base. Gelochelidon, p. 27. 
3'. Length of bill more than three times its depth 
at base. Sterna, p. 27. 
2'. Tail forked for about one fifth its total length, 
outer feathers wide and rounded at tips. 
Hydrochelidon, p. 31. 
GENUS RISSA. 
40a. Rissa tridactyla pollicaris Ridgw. Pacific Kittiwake. 
Appearance gull-like; hind toe minute, with or without a nail; feet 
