1108 A Monograph of the Indian and [No. 131. 



since observed the same of it, — and which, in like manner, continues 

 to lay both while hatching and rearing its excluded progeny of different 

 ages. 



Moreover, what is still more remarkable, in connexion with the facts 

 already stated, it appears that these Cuculine birds of North America 

 do sometimes lay in the nests of other birds; while, like their Eu- 

 ropean relative, they devour all the eggs they find : in opposition to 

 which, may be cited a statement by Mr. Gray, that the European 

 Cuckoo does not uniformly desert her offspring to the extent that 

 has been supposed ; but, on the contrary, " though she leaves the 

 eggs to be hatched by another bird, sometimes at least she takes care 

 of the young bird and feeds it after it leaves the nest, and teaches 

 it to fly'*, as he declares to have personally witnessed in one instance. 

 This much, however, is certain, that a large proportion of the young 

 Cuckoos hatched in England do not see the light till after the parent- 

 birds had left the country : and whatever may be the cause of the 

 singularly early migration of this species, which retires southward 

 at the hottest period of the year, while other migratory species (as 

 observed in captivity,) are directly prompted by decline of tempera- 

 ture to undertake their long journeyt, it has been plausibly enough 

 suggested that it must be in reference to this that the Cuckoo is en- 

 dowed with the instinct of burthening other species with the charge 

 of its offspring ; and it is worthy of remark (though I do not know that 

 the analogy has been before adduced), that in the common British 

 Swift (Cypselus murariusj, which also quits for Southern climes 

 remarkably early, though not so very soon as the adult Cuckoos, the 

 migrative impulse is oftentimes sufficiently intense to impel the parent- 



* Proc. Zool. Soc, 1836, p 104. 



f Having kept numerous migratory birds through the winter in England, I have 

 repeatedly had opportunities of observing that the instinctive impulse to depart 

 was thus incited, becoming moderate, in general, during mild weather, and en- 

 hanced with cold: the birds flapping and fluttering their wings, with beak pointed 

 upwards, and often violently dashing against the roof of their prison, during the 

 evening and night (being very rarely thus agitated in the day time), and con- 

 tinuing to evince this migrative restlessness, at intervals, throughout the winter. 

 Food has nothing to do with it, and one of the most extraordinary circumstances 

 connected with migration is, that the same individuals return to their exact former 

 abode the following season, even captive birds turned loose having repeatedly 

 been known to come back to their place of confinement; and this notwithstanding 

 they travel by night, and perform aerial voyages of such vast extent ! 



