Field Notes. 279 



matter by bleaching, the white weeds are practically vegetable 

 gelatine which, when boiled for ten minutes in twenty or 

 thirty times their weight of water, produces a solidified jelly 

 upon cooling. It is decidedly nutritive, and by digestion may 

 furnish the system with a modicum of sugar. 



Same Cuckoo twice making use of same Nest. Re- 

 ferring to Mr. Massey's note {The Naturalist, August, p. 271), 

 with which I quite agree in the main ; where we differ is, that 

 he considers no instance can be proved of a Cuckoo having 

 laid twice in one nest. I gave an instance which was satis- 

 factory to me, and I quoted several others, and I think I 

 could quote more of a similar character. Mr. Massey asks if I 

 would give him the weight of the two eggs I mentioned in my 

 previous note (p. 237), but as this occurrence must be nearly 

 forty years since, and I did not retain the eggs, never having 

 had a passion for collections, I am sorry I cannot furnish the 

 necessary particulars ; and even if I had the eggs, I question 

 whether this would clear the matter up. 1, however, gave 

 one of the eggs to Mr. J. W. Carter, 15 Westfield Road, Heaton, 

 Bradford. He was with me when I found the nest. I cannot 

 remember what became of the other egg, but I never entertained 

 the least doubt but that I was right in my identification of the 

 eggs. However, if I were wrong, can Mr. Massey be absolutely 

 sure that when he says in his note that he has examined seveH 

 hundred and seventy-two sets of Cuckoo's eggs (and I am not 

 in the least calling his statement into question) that after 

 all they were Cuckoo's eggs beyond the possibility of a doubt ? 

 I am not quite sure, if all the sets of eggs he mentions 

 had been weighed, there may not, after all, be an element of 

 doubt in the matter. Mr. Massey says that he takes it that the 

 instinct of the Cuckoo tells her there would be no room for two 

 young in the same nest, with which I quite agree, if taken in 

 a general sense, but the vagaries of some individual Cuckoos 

 admit of no limit. Individual Cuckoos often violate true 

 instinct much more violent^ than the}^ do M"hen they lay 

 twice in one nest. In support of this, innumerable instances 

 could be quoted, but this does not disprove that Cuckoos are 

 not guilty of such misdemeanour.. — E. P. Butterfield, 

 Wilsden. 



Note. — I have twice in my lifetime found two Cuckoo's 

 eggs in one nest, once at Tanfield, in the nest of a Hedge 

 Sparrow, and once on Dartford Heath, Kent, in the nest of a 

 Tree Pipit. There was no possibility of a mistake in either case, 

 but in each it was perfectly obvious that the eggs w^ere laid by 

 different birds. — R.F. 



1918 Sept. 1. 



