18 
JAEGERS 
KEY TO SPECIES OF STERCORARIUS. 
1. Middle pair of tail feathers wide, and rounded at ends. 
pomarinus, p. 18. 
1'. Middle pair of tail feathers narrow and sharp-pointed. 
2. Middle feathers about half longer than rest of tail. 
parasiticus, p. 18. 
2'. Middle feathers about twice as long as rest of tail. 
longicaudus, p. 18. 
36. Stercorarius pomarinus ( Temm .). Pomarine Jaeger. 
Adults. — Light phase: face, crown, and upper parts, except collar, sooty 
black; throat white, becoming silky yellow on cheeks and around back of 
neck; breast white, chest and sides mottled with sooty. Dark phase: wholly 
dark sooty or plumbeous. All grades are found between the dark and 
light phases. Young: back dusky, feathers tipped with buff; rest of 
plumage dull buff, barred with dusky. Length: 20-23, wing 13.50-14.00, 
tail 8-9, bill 1.45-1.75. 
Distribution. — Northern part of northern hemisphere ; south in winter to 
Africa, Australia, and probably South America; in the United States to 
Michigan, Nebraska, and California. 
Mr. Nelson found the pomarine jaeger largely replacing the other 
two jaegers along the shores of the Arctic Ocean, especially on the 
edge of the ice pack and about the whaling fleet, where it found 
abundant fare. He says that the peculiar twist of its long tail 
feathers makes it conspicuous and easily identified as far as seen. 
When feeding it gives a low, harsh, chattering cry. 
Compared with the parasitic jaeger, the pomarine is a clumsy 
cowardly bird, Mr. Nelson tells us, and is made the sport of its active 
little relative. When met in the air, the pomarine wards off attack 
from one side by a half-closed wing, and from above by raising both 
wings to form an arched shield over its back. One that Mr. Nelson 
saw attacked alighted on the river, and “at every swoop of its 
assailant thrust its head under water, exhibiting the most ludicrous 
terror. ” 
37. Stercorarius parasiticus (Linn.). Parasitic Jaeger. 
Adults. — Light phase: upper parts slaty, becoming blackish on crown, 
wings, and tail; throat and under parts white; sides of head and neck 
white or grayish, tinged with yellow. Dark phase: entire plumage slaty 
or sooty, darkest on crown, wings, and tail. Young: head and neck 
streaked, and under parts spotted and barred with buff and dusky. Length : 
15.50-21.00, wing 12.67, tail 7-9, bill 1.27. 
Distribution. — Northern part of northern hemisphere, breeding in arc¬ 
tic regions; south in winter to New York, Illinois, Colorado, and southern 
California. 
Nest. — A depression in the moss. Eggs: 2. 
38. Stercorarius longicaudus Vieill. Long-tailed Jaeger. 
Adults. — Top and sides of head black ; back slaty ; neck and lower parts 
