400 PETRELS AND SHEARWATERS 



ing excursions round such vessels is often taken on a baited 

 hook. 



Nothing seems to be known of the " courtship " of the Shearwaters, 

 and little enough is known of the breeding habits of any save of the 

 Manx-shearwater. But even in the case of this species our knowledge 

 is very far from complete. Underground nurseries are invariably 

 chosen : rock-crevices and deserted burrows are seized upon when- 

 ever they can be found, and failing these the birds will excavate for 

 themselves. Both sexes take part in this work, and they share the 

 duties of incubation and the care of the young. Only one is reared 

 during the season, and this seems to be fed on regurgitated food, 

 principally oil. And herein, it seems to me, we might profitably make 

 a distinction between "regurgitated" and "disgorged" food, using 

 the former term for food which has been completely changed by 

 digestion, and the latter for such as has simply been " pouched " for 

 the convenience of carriage. Thus the Petrels and Pigeons afford 

 instances of young which are fed upon " regurgitated " food, while the 

 young of herons and cormorants, for example, are fed upon " disgorged " 

 food. Often the head of a fish " disgorged " by a cormorant has been 

 more or less digested, as it were accidentally, but the greater part 

 thereof is taken by the young in its actual raw state. 



Like the young of the storm-petrel and its congeners, nestling 

 shearwaters remain long in the nest, and are similarly clad in nestling 

 down of excessive length and " wooliness." Similarly, like the adults 

 they eject oil when molested. As with the smaller petrels, so with the 

 shearwater, the young are eagerly sought by the natives for the sake of 

 the abundant oil they yield, and for their flesh, which they apparently find 

 palatable in spite of the curiously pungent smell which emanates from 

 petrels of all sizes and ages. The hunters discover their quarry either 

 by means of dogs or by listening for the sounds made by the brooding 

 birds, for they are very garrulous in their burrows. According to 

 Messrs. Ussher and Warren their notes sound like " ah-roo, kuk, kuk, 

 ah-oo" Some of these notes are uttered in a deep voice and some in 



