Letters, Extracts, and Notes. 5.23 



be interesting to draw attention to a case where an inherent 

 dislike for the flesh of a bird has been entirely overcome l)y 

 artificial means. I refer to the case of a trained Peregrine 

 Falcon which has been educated to kill and eat a Rook, the 

 latter species being probably quite immune from attack in 

 the wild state. That falconers have no little difficulty in 

 overcoming this pronounced prejudice is very clearly })rov(d 

 by reading Mr. Harting's instructions on how to "enter" a 

 Falcon to this distasteful quarry .... " Feed her for some 

 time previously on very dark-coloured pigeons, or give her 

 the leg of a black-plumaged fowl to "tire" on, and when 

 she has eventually killed her first Rook (uith a line on) a 

 freshly killed Pigeon should be adroitly thrust up from 

 under the Rook's outstretched wings, and cut open in such 

 a way as to enable the Hawk to get a mouthful of the 

 Pigeon instead of the Rook " [cf. " Hints on Hawks," 

 p. 68). 



With regard to the peculiar mouth ornamentations found in 

 certain nestling birds, jNIr. Swynnerton has brought together 

 a fund of extremely interesting information. Although he 

 does not say so in so many M'ords, he seems to infer that 

 these characters are constant in the species possessing them. 

 When I wrote my ' Ibis ' article in 1907 I was under the 

 same impression, and it was not until 1913 that I realized 

 that the tongue-spots, at any rate, were subject to a certain 

 amount of variation. On July 29 of that year I found a 

 nest of the Common Skylark {Atauda arvensis arvensis) 

 containing three young birds. Upon the tongues of these 

 nestlings the usually conspicuous basal spots were entirely 

 Avairting. Subsequently I have noticed that these basal 

 marks occasionally vary, not only in size but also in shape, 

 and this may sometimes be seen in members of the sarue 

 brood. 



Yours truly, 



CoLLlNGAVOOD IxGKAM, Captaiu. 



Westgate-on-Sea. 



Vj, Mav, 1910. 



