Ill HABITS OF THE CUCKOO 55 



cause theirs during the period of infancy." It is remarkable 

 that some of the species, but not all, both of the Cuckoo and 

 Molothrus should agree in this one strange habit of their para- 

 sitical propagation, whilst opposed to each other in almost 

 every other habit : the molothrus, like our starling, is eminently 

 sociable, and lives on the open plains without 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 widely 

 removed from each other. Many theories, even phrenological 

 theories, have been advanced to explain the origin of the 

 cuckoo laying its eggs in other birds' nests. M. Provost alone, 

 I think, has thrown light by his observations ' on this puzzle : 

 he finds that the female cuckoo, which, according to most 

 observers, lays at least from four to six eggs, must pair with 

 the male each time after laying only one or two eggs. Now, 

 if the cuckoo was obliged to sit on her own eggs, she would 

 either have to sit on all together, and therefore leave those first 

 laid so long, that they probably would become addled ; or she 

 would have to hatch separately each egg 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, the cause of her depositing her eggs in other birds' 

 nests, and leaving them to the care of foster-parents. I am 

 strongly inclined to believe that this view is correct, from 

 having been independently led (as we shall hereafter see) to an 

 analogous conclusion with regard to the South American ostrich, 

 the females of which are parasitical, if I may so express it, on 

 each other ; each female laying several eggs in the nests of several 

 other females, and the male ostrich undertaking all the cares of 

 incubation, like the strange foster-parents with the cuckoo. 



I will mention only two other birds, which are very common, 

 and render themselves prominent from their habits. The 

 Saurophagus sulphuratus is typical of the great American tribe 

 of tyrant-flycatchers. In its structure it closely approaches the 

 true shrikes, but in its habits may be compared to many birds. 

 I have frequently observed it, hunting a field, hovering over 



1 Read before the Academy of Sciences in Paris. L'Institut, 1834, p. 418. 



