1832-3.] HABITS OF THE CUCKOO. 53 



standing on the backs of cattle ; it differs only in being- a little 

 smaller, and in its plumag-e and eggs being of a slightly different 

 shade of colour. This close agreement in structure and habits, 

 in rej3resentative species coming from opposite quarters of a great 

 continent, always strikes one as intereoting, though of common 

 occurrence. 



Mr. Swainson has well remarked,* that with the exception of 

 the Molothrus pecoris, to which must be added the M. niger, the 

 cuckoos are the only birds which caji be called truly parasitical ; 

 namely, such as " fasten themselves, as it were, on another living 

 animal, whose animal heat brings their young into life, wiiose 

 food they live upon, and whose death would cause theirs 

 during the period of infancy." It is remarkable that some of 

 the species, but not all, both of the Cuckoo and Molotiirus, 

 should agree in this one strange habit of their parasitical propa- 

 gation, whilst opposed to each other in almost every other habit : 

 the molothrus, like our starling, is eminently sociable, and lives 

 on the open plains wilhout art or disguise : the cuckoo, as every 

 one knows, is a singularly shy bird ; it frequents the most retired 

 thickets, and feeds on fruit and caterpillars. In structure also 

 these two genera are vvidely removed from each other. Many 

 theories, even phrenological theories, have been advanced to ex- 

 plain the oriuin of the cuckoo lavinn^ its efjos in other birds' 

 nests. M. Prevost alone, 1 think, has thrown liorlit bv iiis obser- 

 votions| on tliis puzzle: he finds that the female cuckoo, which, 

 according to most observers, lays at least from four to six eggs, 

 must pair witli the male each time after laying only one or two 

 eg'^. Now, if the cuckoo was oblized to sit on her own c^'zs, 

 she would either have to :it on all (ogetlier, and therefore leave 

 those first laid so long, that they probably would become addled ; 

 or she would liave to hatch separately each e^g or two eggs, as 

 soon as laid : but as the cuckoo stays a shorter time in this 

 country than any other migratory bird, she certainly would not 

 have time enough for the successive hatchings. Hence we can 

 perceive in the fact of the cuckoo pairing several times, and 

 laying her eggs at intervals, tiie cause of her depositing her 

 eggs in other birds' nests, and leaving them to tiie care of foster- 



* Magazine of Zoology and Botany, vol, i. p. 217. 

 f lu'ad before the Academy of Sciences in Paris. L'lustitut, 1S34, p. 418. 



