Nesting Status of the Black-headed Gull in Yorks. 165 



to have consisted of about twenty pairs of nesting birds. Mr. 

 W. J. Clarke informs me that this nesting colony has varied 

 very considerably in numbers. The eggs of the birds are much 

 harried, partly by Herring Gulls that fly over from the cliffs, 

 but more by boys, and by a collector who visits this guUery 

 each season and takes all the eggs that he can lay his hands 

 upon. Mr. F. Snowdon, of Whitby, has also sent me many 

 valuable field notes. He informs me that on the same moor, 

 about a mile away, there is another breeding station, where, 

 at any rate, since 1908, about 20 pairs have nested. In 

 the following table I give the field notes of each observer 

 under their initials. 



1905. First visit, and saw about a dozen birds and only 

 two nests. (F.S.) 



1906. About 40 to 50 pairs were there, and early in May 

 every egg was taken by a certain collector. On May 

 27th several birds were again sitting. (W.J.C.) 



1910. About 150 pairs were nesting there. (W.J.C.) 



1911. May 29th, visited the mere and found a large number 

 of birds, but I did not disturb them as they appeared 

 to be sitting. (F.S.) 



1912. May 30th, saw about 80 birds, many nests, all with 

 full clutches. (F.S.) 



1913. April 23rd, estimated the birds at about 150. Rather 

 early for nests. (F.S.) 



1915. May 23rd, counted over 100 nests in the rushes sur- 

 rounding the mere. We did not go on the islands, where 

 there were many other nests. On June 6th large numbers 

 of young birds and many eggs unhatched. (F.S.) 



1916. May 17th, saw a large number of nests ; the birds were 

 laying. (F.S.) 



1917. A friend paid two visits and saw about 100 birds. 

 He also saw evidence that the eggs were being regularly 

 collected. (F.S.) 



1918. May i8th, found the larger number of birds at the second 

 breeding station. But a great decline in numbers. (F.S.) 



1919. May 3rd, only 30 birds. No eggs or nests. (F.S.) 



1920. My friend was at Foul Syke several times, and he 

 never saw more than about half-a-dozen birds. I was 

 there once and did not see more than odd birds. (F.S.) 



1920. Mr. Arthur Wallis visited the place, and tells me that 

 - only six or seven, pairs of birds were nesting. (W.J.C.) 



It would appear that in 1915-6 this colony reached its 

 most prosperous stage. Mr. Snowden informs me that in 

 1917 and after, the eggs appear to have been taken on a whole- 

 sale scale, and the numbers nesting there have rapidly declined. 

 This systematic collecting of every egg might have been per- 

 missible during the war, but should it continue, I suggest it 



1921 May 1 



