THE SEA-BIRDS, 369 
black. Their beaks are yellow, and their eyes peculiarly beautiful ; 
but in their extensive tribe there is much diversity of shade, vary- 
ing from a pure white to a dark grey. 
THE STORMY PETREL. 
( Thalassidroma pelagica.) 
Gulls are shy birds, and are caught with difficulty. They 
fly in flocks, and carry on their fishing avocations in the sea 
near the shore. Sometimes they cover the rocks, and when 
disturbed they rise with frightened screams. Occasionally, they 
may be observed on the shore, crouched with wings half extended, 
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