LIFE-HISTORY OF THE HERRING-GULL. 427 



the other, and went through the jerking ceremony without result. 

 The other bird now uttered a low deep note which might perhaps 

 he written as "kerr," and went on to the nest and incubated; 

 later a disturbance among the Gulls sent both off in flight. An 

 interesting point which I have been unable to decide, but which 

 is worthy of attention is, does the hen ever feed the cock by 

 regurgitation when he has been taking the chief share in 

 incubation and has been on the nest for a considerable length of 

 time? It certainly appeared in this instance as though the 

 bird which mounted the other was applying for food when the 

 jerking ceremony was subsequently gone through. On May 16th 

 these nests were again kept under observation. At the first nest, 

 soon after the boat left, one of the birds commenced incubation ; 

 a little later its mate came up and uttered the call which has 

 been termed by Strong and others the " challenge." The sitting 

 bird at once left the nest and the other walked on and incubated 

 the eggs. Later this bird went off ; a Crow settled near, both 

 the Gulls at once flew to the vicinity of the nest, and one of 

 them soon went on. The Crow approached the nest more nearly, 

 the non-incubating bird at once flew up and drove the intruder 

 off. It was noted on various occasions ,that when a Gull's 

 eggs were threatened by Crows the non-incubating bird always 

 hastened to the assistance of the sitting bird. With regard to 

 the second nest referred to on the 14th, it contained two eggs 

 when I entered the blind at 2 p.m. this day (16th). One of the 

 Gulls soon settled near it and stood there a little while. On a 

 Crow flying past the bird went to the nest and settled down on 

 it. Subsequently it went off, but a Crow flying over caused it 

 to run on again. The Gull called in an agitated manner whilst 

 the Crow was about. After one-and a-half hours the sexes 

 changed on the nest, without ceremony. The bird on the nest 

 appeared to take the initiative and walked off, the other, uttering 

 a few guttural sounds, going on. This bird remained on for the 

 last hour and a half I was there. The non-sitting bird in both 

 cases always stood near at hand. 



This nest, as previously noted, contained two eggs at 2 p.m. ; 

 when I left at 5 p.m. it held three. At about 4.30 p.m. I noticed 

 that the sitting bird was very restless, and I have no doubt that 

 it was the second bird to go on that laid the egg. Another nest 



