230 Letters, Extracts from Correspondence, Notices, ^c. 



XXIII. — Letters, Extracts from Correspondence, Notices, ^c. 



We have received the following letters : — 



To the Editor of ' The Ibis.' 



Hastings, January 8, 1863. 



Sir, — My attention has just been called to a paper published 

 in 'The Ibis/ No. XVI. Oct. 1862, by M. Charles Bolle, of 

 Berlin, in which he describes what he imagines to be a new 

 species of Anthus, and proposes to give it the name Anthus 

 herthelotii. 



My excuse for troubling you with some remarks on the claims 

 of the bird described by M. Bolle to be considered as a new 

 species must rest upon the reference M. Bolle has made to my 

 delineation of the Anthus pratensis, Bechst., in my ' Sketch of 

 Madeira,' Murray, 1851, and in the 'Annals and Magazine of 

 Natural History,^ vol. xii. p. 58, and vol. xv. p. 430. 



M. Bolle introduces his reasons for establishing a new species, 

 by saying that he has been apt to lay too much stress upon the 

 power of climate to influence the tints of the plumage and the 

 habits of birds. M. Bolle has doubtless observed that, in the 

 climates of which he treats, the tints of the plumage of many of 

 our common European species are considerably modified. I 

 would instance the Fringilla cannabina, Linn., which retains its 

 carmine plumage through the year; the Larus argentatus, 

 Briinn., which obtains its mature garb at an earlier period than 

 in Europe; the Strix flammea, Linn., which is somewhat darker 

 than in Europe; the Sylvia atricapilla, Lath., which assumes 

 sometimes so dark a hue as to have led Sir W. Jardine to describe 

 it as a different species ; with several other examples familiar to 

 naturalists who have visited these semi-tropical regions. It is 

 well known to travellers in Central Africa that all chemicals are 

 so largely affected by the climate as to make photography 

 impossible there ; and, whether we can account for it or not, 

 the fact remains that the chemical secretions which produce 

 colour in the plumage of birds are in a greater or less degree 

 influenced by the mysterious agency of climate. That the habits 

 of birds are modified by climate is proved by the non-migratiou 

 of the Woodcock, the Blackcap, the Swift, the Quail, the Petrel, 

 and other birds from the regions of which M. Bolle writes. 



