430 Correspondence. [july 



Maine and on page 45 for one which relates to the Atlantic Ocean. Cor- 

 rections as to authorship should therefore be made in the case of the fol- 

 lowing titles appearing on page 72 of the Index: 



Carpodacus purpureus at Portland, Maine, in winter. 



Early appearance of Empidonax minimus at Portland, Maine. 



Unusual nesting site of Dendroica virens. 



Winter notes from Portland, Maine. 



American Crossbill at sea. 

 These were pubhshed by Captain Brown. 



Yours very truly, 



N. C. B. 



Concealing Coloration. 



Editor of ' The Auk ' : — 



Dear Sir: — The naturalists answer about this or that creature, whose 

 wonderful background matching I show, that he has no use for concealment. 

 Here they are in their own field though venturing far beyond scientific 

 knowledge; but this does not in the shghtest degree affect the all the more 

 interesting fact of his astoundingly perfect background painting. And 

 because in all these cases, these creatures (supposed to need no concealment) 

 nevertheless have it fro7n the very situation from which some animals see 

 them. I do not beheve that so wonderful an equipment is for nothing, 

 and I doubt the naturahsts' assertion that it does not help the wearer. 



Most naturalists also deride the idea that so vast a variety of costume 

 as that of the forest fauna could all be subject to one law of conceahng color- 

 ation. 



Conceahng coloration is simply that which passes the wearer off for any 

 details of the scene, and of these the forest contains of course a boundless 

 variety. To test at the start the probabihty of such a general law, turn 

 from the complexities of the forest to the simplicity of other realms, the 

 :sea, the sands, the snow — look at the inhabitants of all these more or less 

 monochrome parts of the world, and you will find that everywhere the 

 mearer to one single color note is the scene the "nearer to a corresponding 

 •single color note is the animal's costume. 



Let them tell me why this so widespread resemblance of inhabitants to 

 background should suddenly cease when one comes to the complex scenery 

 ■of the woods, which offer a hundred models for counterfeiting where the 

 sea, snow or desert offers one. 



Therefore, since each different forest costume is a dupHcate of some 

 part of the scene, the catchword that if in the same woods any particular 

 costume is a concealer the others are not, boils down to the same absurdity 

 as saying that if one of the things they counterfeit is real, the others aren't 

 — in other words, if the tree trunk is real, the leaves are not. 



