Common Cuckoo. 283 



The next question examined is c whether the same hen Cuckoo 

 lays eggs of the same colour and markings only, and is so 

 limited to the nests of but one species ? or else, does the same 

 individual lay eggs of different colour and markings, according to 

 the character of the eggs amongst which her own will be 

 intruded ?' Both these theories have their advocates ; those in 

 favour of the last view advancing the hypothesis that the sight of 

 the eggs lying in the nest has such an influence on the hen which 

 is just about to lay, that the egg which is ready to be laid assumes 

 the colour and markings of those before her ; and for this, phy- 

 siological reasons are adduced, and analogies, not forgetting the 

 well-known and successful experiments of the patriarch Jacob.* 

 But Dr. Baldamus rejects this opinion, and contends for the 

 other view (viz. that the same Cuckoo lays eggs of one colour 

 and markings only, and so is limited to the nests of but one 

 species) ; and this he proves by personal experience and observa- 

 tion ; by the fact that he has found two differently marked 

 Cuckoos' eggs in one nest ; that he has also found similarly 

 marked eggs, laid by one and the same Cuckoo, in the nests of 

 different species ; and that he has found Cuckoos' eggs (though 

 rarely) in such nests as have not yet received any eggs of the 

 owner ;t in which case the Cuckoo is without any pattern of a 

 fixed form of colour for its egg. All these points in the argument 

 are very carefully worked out at considerable length, and a large 

 array of proofs and instances brought forward to support his 

 views ; and then our author deduces the conclusion, that all 

 experience hitherto known declares in favour of his assertion ' that 

 every Cuckoo lays eggs of one colouring only, and consequently 

 (as a general rule) lays only in the nest of one species :' and he 

 sums up his argument as follows : ' every pair, or rather each 

 individual Cuckoo, is endowed with the instinct to lay its eggs in 



annually from four to six eggs), the difficulty is at once disposed of, if Dr. 

 Baldamus' theory is correct, inasmuch as the great similarity of the egg of 

 the Cuckoo to those of the nest in which it is placed, may deceive human 

 eyes no less than those of the foster parents. 



Genesis xxx. 37 et seq. 



t This is corroborated in the Naturalist for 1852, p. 33. 



