250 BRITISH SEA BIRDS. 



to those found in the Fulmar a nearly clear oil, 

 mingled with the jaws of cuttlefish, and scraps of 

 sorrel. 



The Fork-tailed Petrel resorts to its breeding 

 stations to nest in June. Although gregarious 

 during this period, its colonies are never so large 

 as those of the Fulmar. Most probably the bird 

 pairs for life, and returns season by season to 

 certain spots to rear its young. The largest colony 

 of this Petrel known to me is at St. Kilda. Here 

 its principal colony is located on the island of Soay, 

 but there is another and smaller one on Doon, and 

 doubtless others on Borreay. At the colony on 

 Doon, the ground was full of long, winding burrows, 

 probably disused nesting holes of Puffins and Shear- 

 waters, and in these the Fork-tailed Petrels had 

 made their nests in some cases one earth accom- 

 modating several pairs of birds. Usually the 

 selected burrows are in the loamy soil near the 

 summit of the cliffs ; but, in some cases, the birds 

 will select a hole, or crevice, in ruined masonry, or 

 in rocks. At the end of the burrow, or crevice, a 

 scanty nest of dry grass is formed, but in some 

 cases no provision whatever is made. Here the 

 female deposits a single egg, white, with a zone 

 of dust -like brown specks round the larger end. 

 These eggs are remarkably fragile, and very chalky 

 in texture. The Fork-tailed Petrel is a close sitter, 

 remaining brooding over its egg until dragged out. 

 Many nests may be found within an area of a few 



