The Zoologist— May, 1874. 3967 



course due to the fact of the author having mended the old garment 

 with pieces of new cloth, and when this process of mending had 

 been completed, ignoring the new patches in his preface, but 

 making his strictures on our ignorance apply alike to the old and 

 to the new. 



The cuckoo is a bird of such general and absorbing interest that 

 we are glad of every scrap of information respecting it. I am aware 

 it is treacherous ground to enter on, but he who hesitates to diffuse 

 either fact or theory, in the fear of displeasing the captious, or the 

 prejudiced, is unworthy to hold an Editor's pen. The third and 

 fourth chapters, treating exclusively on the cuckoo, are chiefly 

 in reference to what is published in Montagu's ' Ornithological 

 Dictionary,' but incorporating original and characteristic observa- 

 tions. Thus, after mentioning the extraordinary fact related by 

 Dr. Jenner, of two hedgesparrow's eggs containing living foetuses 

 having been found under a young cuckoo about a fortnight old, 

 and Colonel Montagu's conjecture that, contrary to the case in the 

 generality of birds, cuckoos have the power of retaining the egg in 

 the ruterus after it is perfected, and that while there the embryo is 

 progressively advanced towards maturity by the internal heat of 

 the parent's body, Mr. Blackwall adds — 



" Now without having observed a single circumstance in the whole course 

 of my inquiries which at all tends to corroborate this opinion of Montagu's, 

 I have discovered a curious fact which appears to render such a supposition 

 altogether unnecessary. On the 5th of May, 1829, I saw a cuckoo in the 

 act of watching a pair of titlarks construct their nest. The larks had just 

 commenced building, and did not seem to be at all disconcerted at the 

 presence of the cuckoo, which sat on the ground, about seven or eight yards 

 from the spot, attentively observing them, and when disturbed flew away 

 with great reluctance, and only to a short distance. This nest, which was 

 on Kersal Moor, where the races are annually held, was too distant from 

 my residence to permit me to examine it frequently, and to make such 

 numerous and minute observations as I wished ; but on the 12th of May 

 I again visited it, in the confident expectation that it would contain a 

 cuckoo's egg, and I was not disappointed. I may further remark, in con- 

 firmation of this discovery, which, by exhibiting a curious and hitherto 

 unnoticed instinctive propensity of this bird, forms an interesting addition 

 to its history, that cuckoos almost invariably deposit their eggs in the nests 

 of other birds as soon as those birds begin to lay — not unfrequently, indeed, 

 immediately after the exclusion of the first egg ; and Mr. Baker informs me 

 that he saw the hen of that pair of cuckoos which be observed so closely 



