426 THE ZOOLOGIST. 



piping). The female was subsequently fed by tlie male by 

 regurgitation. 



I saw several instances of this ceremony, andi n more than 

 one case one of the birds bobbed the head until the motion was 

 taken up by the body, and eventually the bird lay flat on the 

 ground on its belly ; it then worked the tail from side to side, 

 much in the manner of a male when treading. The meaning of 

 this ceremony is not clear to me, but it undoubtedly has a strong 

 sexual significance. 



Having put up a blind on another island, I spent some hours 

 watching the Gulls there on May 14th. The first nest under 

 observation here contained one egg on May 12th and held two 

 on the 14th. After the boat left, one of the Gulls stood near 

 this nest for some time ; two Crows then came along, and the 

 bird at once covered the eggs, incubating them. It sat some 

 time and then left the eggs, and was apparently fed by its mate 

 after the jerking ceremony had been gone through ; it then 

 returned and incubated. This nest subsequently held three eggs. 



The second nest under observation here was empty on the 

 12th, and held one egg on this day (14th). One of the Gulls, 

 after standing near the nest for some time after the boat left, 

 eat on the egg ; it left for a .minute or so more than once, but 

 soon returned. Its mate came and stood near. The sitting bird 

 left the nest and indulged in the head-jerking ceremony with no 

 result ; it then returned to the nest and incubated. Later 

 the same bird was incubating when [the other approached, and 

 lowering its head, uttered the challenge call. The incubating 

 bird at once rose and ran to the other ; both then uttered the 

 call, not unlike the clucking of a hen, previously mentioned, and 

 bobbed their heads up and down. The bird which had not been 

 sitting then went to the nest and egg and partially covered them 

 for a few seconds. It then went off, and the bird which had 

 been incubating all the afternoon mounted it and copulation 

 ensued ; evidently it was the male that was taking the major 

 share of the incubating duties at this stage. Shortly after a 

 Crow flew near once or twice ; the male uttered an agitated call 

 (evidently disturbed by the proximity of the Crow to the egg), 

 and immediately went to the nest and resumed incubation. 

 Later it left the nest and preened its plumage ; it approached 



