1112 The Zoologist— March, 186S. 



It is at this period of its existence that the young cuckoo is said to 

 possess, or to acquire for a time, the note of ils foster-parents,* what- 

 ever it may happen to be ; but this point in its history requires 

 corroboration, as, though asserted by many, it has never yet been 

 satisfactorily settled. And then again, when they have at length 

 attained their full size, the young cuckoos, though left to their own 

 devices, and without their elders for their guides, as all other migratory 

 birds have, follow towards the end of September, in the track of their 

 parents who have gone long before, and migrate to a warmer climate: 

 though what instinct teaches them when to go, or whither to bend their 

 course, who shall say ? Indeed, to my mind, this is one of the most 

 astonishing points in their life-history which we have now touched 

 upon. 



And now I come to the most remarkable peculiarity of all : and 

 indeed amongst these so many anomalies which we have seen to 

 belong to this extraordinary bird (and the more one studies its habits 

 the more numerous, and the more apparent do they become), there is 

 nothing so strange, or indeed so startling, as the opinion put forth, as 

 I said just now, in Germany by Dr. Baldamus, and afterwards followed 

 up and demonstrated by proofs of apparently the most satisfactory 

 character, on the part of himself and his friends, — that the cuckoo, 

 while she lays her eggs singly in the nests of other birds, is able to 

 assimilate them in colour to the eijys of those birds whose nests site 

 selects: f and thus it is by no means an uncommon occurrence to see 

 the egg of the cuckoo taken from a hedgesparrow's nest, partaking of 

 a greenish blue tinge ; another from the nest of a robin of a reddish 

 hue; another from a pipit's nest of a brownish colour; and so on 

 through the twenty or thirty species, in whose nests the egg of the 

 cuckoo has been found. Feeling keenly, as I do, the startling nature 

 of this bold statement, and tho scepticism it is likely to call forth, I 

 will not linger over it with any comments of my own, but proceed at 

 once to give a short resume' of the article in question. 



Dr. Baldamus begins his paper by calling attention to the great 

 variety in colouring as well as in marking in a collection of cuckoo's 

 eggs, and the astonishing resemblance these eggs severally bear to the 

 eggs of a variety of small birds usually chosen as the foster-parents of 

 cuckoos, — a fact which he says was well known to the great ornitho- 

 logists and oologists of Germany, including Naumann, Thienemann, 



* Thompson's ' Natural History of Ireland,' vol. 1, p. 361. 

 t 'Zoologist,' 3988. 



