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THE SEQUENCE OF PLUMAGES OF THE ROOK. 



With Special Reference to the 

 Moult of the " Face." 



BY 



H. F. WITHERBY. 



(Plates 4-11.) 



Introductory. 



It has always been a disputed point as to whether the 

 Rook {Corvus f. frugilegus) gets its bare " face " by means 

 of abrasion of the feathers or by a moult. Most ornith- 

 ologists have favoured the moult theory or have 

 regarded it as a " natural pecuharity." This conclusion 

 has been reached, however, by inference rather than 

 by actual experiment. A few somewhat trivial experi- 

 ments have been made with captive birds, but no 

 proper investigation of the subject has hitherto been 

 undertaken so far as I am aware. 



Waterton {Essays on Natural History, First Series, 

 1838) appears to have thought that he had solved the 

 problem when the feathers on the face of a young Rook, 

 kept in a cage by a keeper, began to fall out in the middle 

 of August. Unfortunal^ely the bird met with a fatal 

 accident at the end of August, so that although Waterton 

 had good reason for saying " that the feathers fall off 

 from the root of the Rook's bill, by the order of nature," 

 he did not realize that had the bird lived a Httle longer 

 new feathers would have grown " by the order of nature," 

 and that the bird would have had a fully-feathered face 

 as part of its first winter-plumage. 



Knox (Zoologist, 1844, pp. 628-33) made a closer 

 investigation, but for want of sufficient care he also 

 came to wrong conclusions. He kept young Rooks in 

 captivity and found that they moulted normally and 

 attained feathered faces in their first winter-plumage. In 

 the spring one of them began to lose its nostril-bristles, 

 but Knox concluded that this was on account of friction 



