460 Correspondence. \r\ u ^ 



LOct. 



CORRESPONDENCE. 



Protective Coloration. 



Editors of 'The Auk': — ■ 



Dear Sirs: — I wish to record in 'The Auk' the main results, up to date, 

 of my study of Protective Coloration. These were all foreshadowed in my 

 first article in 'The Auk' (XIII, 1896, pp. 124-129, 10 illustr.), and, later, 

 in a paper published in the Transactions of the Entomological Society of 

 London, 1 I was able to present the subject of patterns in a much more 

 developed shape. What I now wish to record is mainly what I communi- 

 cated to the annual meeting of the A. O. U. in 1904, but which the re- 

 porters failed to get, so that it remains, as yet, unpublished. It is this: 

 It now proves to be the case that all patterns and colors, upon all animals 

 whatsoever, except such as live in the dark, or are neither predatory nor 

 preyed upon, are, when seen against the background against which their enemy 

 (or prey) would see them at the critical moment, in expressibly perfect pictures 

 of this background, and therefore obliteratively colored. The marvellous 

 perfection of the scene thus painted on each aminal is, of course, only 

 appreciable by painters. It is such that the different parts of any resplen- 

 dent bird's costume, peacock, wood duck, or blue jay, make, when sepa- 

 rated, and merely slightly rearranged, a scene of their habitat that defies, 

 in its realism, all painters. 



The one thing that has kept even artists from beginning to see this fact 

 is that no one has perceived that obliterative coloration means matching 

 a certain background, not a general resemblance to surroundings. This 

 old phrase means actually nothing. For instance, a white heron and a 

 brown frog may be in the same surroundings, yet the heron sees the brown 

 frog against brown mud, while the frog sees the white heron against the 

 sky\ — the nearest match possible, and one which effaces the heron's tell- 

 tale upper contours, especially when the sky is white, or at night. Till 

 now, however, observers have regarded the frog and heron, and discussed 

 them, from men's standpoint, and called one. protectively colored, and one 

 conspicuous. This principle is universal in nature. 



My son and I are now sending to the press a book demonstrating my 

 results up to now. Fortunately it involves no theory whatever, but is all 

 shown to be susceptible of absolute occular proof. It does not say that 

 patterns and countershading exist to conceal animals, but shows that they 

 do always conceal them. 



Abbott H. Thayer. 



1 Protective Coloration in its Relation to Mimicry, Common Warning Colors, and 

 Sexual Selection. Trans. Entomol. Soc. of London, 1903, Part IV, pp. 553-569. Dec, 

 1903. 



