1 842. J Malayan species of Cuculidce. 1111 



often classed, and which also live in flocks, brut construct a number 

 of nests in society, the relative proportion of the sexes in the several 

 breeding groups is extremely irregular, as if these birds also did not 

 separate off into pairs. This alleged circumstance might be advan- 

 tageously borne in mind when studying the habits of the Keelbills 

 ( Crotophaga) of tropical America, those very curious gregarious 

 Cuculidce of the West Indies and adjacent countries, of which the 

 best account yet published is given in the Annals of Natural History 

 for November, 1839. 



Among the variety of curious phenomena presented in the Natural 

 History of the European Cuckoo, it is remarkable that this bird 

 devours what eggs there may be in a nest into which she introduces 

 her own, so that any eggs that may be found together with that of the 

 Cuckoo, have been laid subsequently to the deposition of the latter* : 

 nevertheless, it appears that she spares that of her own species, or 

 perhaps her own previous egg, as many instances have been recorded 

 of two Cuckoo's eggs being found together, in general unaccompanied 

 by those of the rightful owners of the nest. Hence, I incline to the 

 opinion that she hastens to disburthen herself of her own egg, being 

 very liable to be disturbed and driven from the nest by its legitimate 

 possessors; and that then, if continuing unmolested, she picks out any 

 other eggs there may be, but that when finding another laid by her 

 own species, she is unable to distinguish that from her own, and so 

 leaves both. From many experiments which I have tried with a 

 view to elucidate this matter, I have found that, generally, in each 

 case when a strange egg is put into a nest before the owner of it had 

 begun to lay, that nest is deserted, — if it be placed along with the 

 owner's eggs, it is very commonly ejected, — but, if substituted for 

 the latter, then the duped bird will either incubate it alone, as the 

 case may be, or lay other eggs to it, and sit on all. It is a question to 

 be determined whether the egg of any Cuculine bird be ever found 

 in nests with a domed top, as has been asserted, wherein to the bird 

 could not have laid it, but must have placed it with the foot or bill ; 

 and what renders it unlikely that this should ever be the case with 

 the British Cuckoo, and such others as resemble it in displaying 



* See Mag. Nat. Hfat. 1835, p. 334. 



