254 NATATORES. 
northern parts of the United States, and in the Polar 
regions, sit closely on their eggs; while the species 
that breed in more southern latitudes incubate only 
during the night or in rainy weather. 
Of the family of Gulls, so well known and so 
widely diffused, we notice first the species bearing 
the name of Bonaparte, in allusion to the well-known 
naturalist. This bird is found at times in great 
numbers along our sea-board, from the Bay of Fundy, 
and even higher latitudes, to the coast of Florida. 
It has also been observed sweeping over the Ohio 
river, in search of small fishes or floating garbage. 
When examined after death, the stomachs are found 
to contain shrimp, young fishes, fatty substances, and 
sometimes coleopterous insects. In Spring, when 
the shad enter the bays and rivers to deposit their 
spawn, this Gull begins to show itself, as if for the 
purpose of preying upon the shoals, which, however, 
is not the case. It is described as being very gentle 
in some localities, scarcely heeding the presence of 
man. 
The Great Black-backed Gull, the largest of the 
tribe, delights in sailing over the rugged crags of 
Labrador. He moves in wide circles, with loud, 
harsh cries, far above the multitudes of smaller birds 
below, who instinctively dread the approach of this 
tyrant, or prepare to defend their young broods from 
its powerful beak. The fish sink deeper as he ap- 
proaches, while the other Gulls fly as fast as possible 
from their enemy. At length he spies, perhaps, the 
carcass of a whale, and, with fierce cries, darts down 
ee. 7 ST 
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