106 



the fields." This agrees with my own observations. Acci- 

 dental varieties will generally be found to be smaller and 

 weaker birds than those which are truly characteristic of 

 the species. As these young birds increase in age, and 

 gain constitutional power, the secretions become perfect, 

 and the plumage assumes its natural colours. The as- 

 sumption of white feathers by old birds is probably the 

 effect of the converse operation of this physiological law. 



Malformations of the beak are by no means uncommon 

 among the species of the genus Corvus, particularly in the 

 Rook, and some remarks by John Blackwall, Esq., in his 

 Researches in Zoology^ refer to a question not yet entirely 

 set at rest. 



" A Rook preserved in the Manchester Museum, has its 

 mandibles crossed near their extremities, but so slightly, as 

 not to have interfered materially with the mode of pro- 

 curing food usually employed by that species, as is clearly 

 evinced by the denuded state of the nostrils and the ante- 

 rior part of the head, both of which are entirely destitute 

 of feathers. Another specimen, in the possession of Mr. 

 R. Wood, a zealous collector of objects in natural history, 

 residing in Manchester, has the mandibles greatly elon- 

 gated, and much curved. Now it is evident that the bird, 

 possessing a bill thus formed, could not thrust it into the 

 ground in search of worms and the larvae of insects, as the 

 Rook is known to do habitually; and, accordingly, the 

 plumage at the base of the bill of this individual, and the 

 bristly feathers which cover its nostrils, are very con- 

 spicuous : not having sustained the slightest injury. The 

 opinion, entertained by many persons, that the naked con- 

 dition of the nostrils and anterior part of the head is an 

 original peculiarity in the Rook, is thus satisfactorily 

 proved to be incorrect : indeed the fact that young Rooks 

 exhibit no deficiency in these particulars, is sufficiently 



