49 
This is the largest of the Jaegers. It resembles the other two species in coloration so 
closely that its separation is difficult except by size and in adult condition. The species 
occurs in two colour phases and in all intermediate stages. 
Distinctions. Elongated middle tail feathers of adult are wide and twisted at the 
tip so as to lie in a vertical instead of a horizontal plane. 
Field Marks. The broad, elongated, twisted tail feathers are propably the best 
field marks. 
Nesting. On ground, in grass. 
“Distribution. Breeds on the islands and mainland in the Arctic across the continent. 
Occurs on the sea coasts farther south, only as a migrant. 
37. Parasitic Jaeger. FR.—LE LABBE PARASITE. Stercorarius parasiticus. L, 17° 
(Tail 8-25, projection of middle feathers beyond outer ones 3-25.) This species occurs 
in two colour phases, a light, and a dark one. In the dark phase the general colour 
is dark brown slightly lighter below and with a black cap. In the light phase the under- 
partes breast, neck, and face are white, with black cap. Intermediate stages of coloration 
also occur. 
Distinctions. The smaller size of this bird should distinguish it from the preceding 
in all plumages. In the adult, the middle tail feathers project only 3 inches beyond the 
others instead of 7 inches as in the next species and are slender instead of broad and twisted 
as in the last species. Immature birds of the Long-tailed species, not having the long 
tail feathers, are almost exactly similar to this species, and can best be distinguished by 
the colour of the shafts of the primary feathers. In the Parasitic, the shafts of the three 
first feathers are white and the remainder are progressively darker as they succeed each 
other on the wing. In the Long-tailed, there is an abrupt darkening of colour of the shafts 
after the third primary. 
Field Marks. Small projection of the middle tail feathers as above and their not 
being twisted make a field mark of fair reliability in adult birds. 
Nesting. On ground, on the moors and tundras of the north. 
Distribution. Breeds in the Arctic across the continent and is much more common 
on Peat in migration than inland, where it is a very rare though possibly a regular 
straggler. 
This is the only Jaeger that is ikely to be met with in the interior on 
the Great Lakes. Other species have been recorded, but upon investigation, 
except in one instance, they have been found to be young birds incorrectly 
identified, usually on the ground of their lack of elongated tail. 
38. Long-tailed Jaeger. FR—LE LABBE A LONGUE QUEUE. Sfercorarius longi- 
caudus. L, 21. (Tail 13-25, projection of centre feather beyond outer ones 8.) Very 
similar in coloration to the preceding, but the long slender middle tail feathers project 7 
or 8 inches beyond the others instead of only 3. 
Distinctions. The Long-tailed Jaeger although having nearly the measurements 
of the Pomarine, owing to the great tail length being included, is a much smaller bird 
than either of the other two species. Size should distinguish it. Juveniles are often con- 
fused with the Parasitic but the wing characters given under that species are diagnostic. 
Field Marks. It is possible to separate only adult Jaegers in life; the long middle 
tail feathers being the best guide. 
Nesting. Similar to that of the other Jaegers. 
Distribution. Breeds in the Arctics of Europe, Asia, and America. Is only of rare 
occurrence on east coast. 
Though the Long-tailed Jaeger has been recorded on the Great Lakes 
most of such occurrences are misidentifications of juveniles of the preceding 
species. 
FAMILY—LARID®. GULLS AND TERNS. 
General Description. The Gulls and Terns are long-winged swimmers, easily separable 
from the Jaegers by the shape and construction of the bill which shows a single continuous 
surface without distinct parts or joints (Figures 4, 5, p. 18). The colours of the adult 
are usually pure white, with white, pearl-grey, or black mantles, often with black wing 
tips, hood, cape, or cheek spots. 
