PDF - Wallace Online

A THEORY OF BIRDS' NESTSnatural phenomena Do 1 they teach us anything of the wayin which nature works, and give us any insight into thecauses which have brought about the marvellous variety, andbeauty, and harmony of living things? I believe we cananswer these questions in the affirmative ;and I may mention,as a sufficient proof that these are not isolated facts, that Iwas first led to see their relation to each other by the studyof an analogous though distinct set of phenomena among insects,that of protective resemblance and " mimicry."On considering this remarkable series of correspondingfacts, the first thing we are taught by them seems to be, thatthere is no incapacity in the female sex among birds to receivethe same bright hues and strongly contrasted tints with whichtheir partners are so often decorated, since whenever they areprotected and concealed during the period of incubation theyare similarly adorned. The fair inference is, that it is chieflydue to the absence of protection or concealment during thisimportant epoch, that gay and conspicuous tints are withheldor left undeveloped. The mode in which this has been effectedis ifvery intelligible,we admit the action of natural andsexual selection. It would appear from the numerous casesin which both sexes are adorned with equally brilliant colours(while both sexes are rarely armed with equally developedoffensive and defensive weapons when not required for individualsafety), that the normal action of " sexual selection " orof other unknown causes, is to develop colour and beauty inboth sexes, by the preservation and multiplication of allvarieties of colour in either sex which are pleasing to theother. Several very close observers of the habits of animalshave assured me that male birds and quadrupeds do oftentake very strong likes and dislikes to individual females, andwe can hardly believe that the one sex (the female) can havea general taste for colour while the other has no such taste.However this may be, the fact remains, that in a vast numberof cases the female acquiresas brilliant and as varied coloursas the male, and therefore most probably acquires them in thesame way as the male does that is, either because thecolour is useful to it, or is correlated with some useful variation,or is pleasing to the other sex. The only remainingsupposition is that it is transmitted from the other sex, with-K