Jan.,1913 CONCEALING AND REVEALING COLORATION O1? ANIMALS 11 That there are almost innumerable cases of concealing coloration, in varying degrees of perfection, is so generally conceded that it needs no argument or ci- tation 6f instances; and some species are so colored as to easily escape observa-
tion in such a great variety of situations as to make quite unnecessary the Messrs.
Thayers' elaborate, interesting, and in the main perhaps correct, explanation of how different type s of broken patterns are suited to different types of back- ground. Difference of opinion is found only when we come to discuss certain definite species or to decide how nearly universal the phenomenon is. That there are many cases of clearly revealing coloration (such as 'the bison above mentioned) is usually admitted, even by the most radical advocates of the other side of the problem, though often in their generalizations they use language which plainly contradicts their admissions of exceptions. Among animals which xvould apparently be as much benefitted by concealment as others, there are such numerous unexplained inconsistencies as may well cause one to hesitate about wholesale declarations. Many of the explanations offered utterly fail to explain. One must wonder if the assertion that white herons are concealingly colored be- cause they are seen by their prey or their enemies against a 'white sky is at all satisfactory to anyone familiar with the range, habits and habitats of this and other herons. Is' it not more often seen in solid white, outlined against a deep blue, leaden or gray sky, or a dark bank, or a solid bank of foliage? At any rate, before the white heron was exterminated over most of its former range, it was found, at least in many places, in the same habitat, and, so far as one may judge, with practically the same feeding habits, as the blue and green herons. Such instances as this, and they are quite numerous, should not be lightly passed over. It does not help matters to say that if we knew more of the intimate life relations of these animals we would find all to be concealingly colored, because that is a mere assertion. Another large class of inconsistencies involves those species of which the male is radically different in color from the female. Forced explanations are not conducive to scientific progress. Taking the redwing as a much discussed ex- ample, it has been asserted that the male is concealingly colored because it is seen by its enemy, the hawk, from above, against the dark mud and dark foliage of its swampy habitat, and that the lighter wing-patch would be easily mistaken for a flower. Yet over a large part of its range (including, of course, the various slightly differentiated species and subspecies) during a large part og the year it finds no dark mud or dark foliage as a background. Species should be con- sidered in relation to their whole range and to all other species and other ele- ments of their environment. Even .more difficult are those species of which the male is much like the female during part of the year, but wears more conspicu- ous colors during the nesting season. The 'theory that the conspicuous color is assumed in order that the male may attract ?the female is hardly satisfactory. The theory that the male is so colored in 6rder to attract enemies from the nest may possibly have some weight, especially in ;?iew of the habit developed by other species of leading enemies from the nest by fluttering along the ground as if woundz ed. Such species as the bobolink and lark bt?nting, the males of which, more con- spicuously colored, rise into the air and then sing as they glide downward as if purposely to attract attention to their alighting-place, afford a chance for obse. rva- tions of value on this point, if they have not been made, by noting in a great num- ber of cases whether the bird glides down toward the nest or away from the nest. An objection to this theory is that many cf the conspicuously colored males assist in feeding the young when hatched, and some, at least, habitually feed the female
