PETRELS. 525 
on the water in great composure in the most tremendous seas; but it is observed 
that in heavy gales they fly extremely low, generally skimming along by the 
surface of the water. They are extremely greedy of the fat of the whale, and 
though few should be seen when a whale is about being captured, yet, as soon as 
the flensing process commences, they rush in from all quarters, and frequently 
accumulate to many thousands. They then occupy the greasy track of the ship; 
and being audaciously greedy, fearlessly advance within a few yards of the men 
FULMAR PETRELS (J 11 at. size). 
employed in cutting up the whale.” Highly gregarious during the breeding-season, 
the fulmars then collect on the turfy ledges of the St. Kilda cliffs in thousands. 
The single white egg is laid either in a slight nest of dried grass, or on the bare 
ground; and although the birds sometimes excavate a hollow of a few inches deep 
in the turf, they as often nest on its surface. 
Nearly allied to the fulmar is the silver-grey petrel (Thalassoica 
glacialoides ) of the Pacific and Southern Atlantic, distinguished by 
its more slender beak, in which the nasal tubes are shorter and more depressed, with 
their upper border concave. This species extends nearly as far south as the 
Antarctic pack-ice, where it is replaced by the snowy petrel (Pagodroma nivea ),—a 
Allied Genera. 
