364 IKTEODTTCTION TO ZOOLOGY. 



285) annually take possession of an island about tliirty acres 

 in extent, and build their nests* In Ireland, the Black-headed 

 Gulls frequent, for the same purpose, the gravelly beach of a 

 portion of Eam's Island in Lough Neagh ; and so closely are 

 the nests placed over the ground, that ISIr. W. Thompson 



Fig. 285.— Black-headed Guli. 



informs us, that he and some friends, when visiting the place, 

 had to use gi-eat circumspection in putting down their feet, 

 that they might not do injury to the nests or eggs. This spe- 

 cies, as stated by the gentleman just mentioned, is that which 

 is most abundant in Belfast Bay, and not the one to which the 

 name of" Common Gull " [L. canus) is appHed. Their evolu- 

 tions are extremely varied and beautiful, exhibiting both power 

 of wing and grace of movement. 



Of the Petrels, the best known species is that which ia 

 the smallest of British web-footed birds,, the Stormy Petrel 

 {Thalassidroma pelagica). They crowd round vessels before 

 and during stormy weather, partly for the sake, it is supposed, of 

 shelter, and partly for that of food. Sailors regard them with 

 superstitious feelings, and have long given them the name of 

 " Mother Carey's Chickens," from some hag of the olden time, 

 whose name would have passed into obUvion had it not been 



♦ Bishop of Norwich's Familiar History of Birds, vol. ii. p. 24G. 



