$74 The Descent of Man. Tart II. 



and red-grouse serve as a protection ? Are partridges, as they 

 are now coloured, better protected than if they had resembled 

 quails ? Do the sligiit differences between the females of the 

 common pheasant, the Japan and gold pheasants, serve as a 

 protection, or might not their plumages have been interchanged 

 with impunity ? From what Mr. Wallace has observed of the 

 habits of certain gallinaceous birds in the East, he thinks that 

 such slight differences are beneficial. For myself, I will only 

 say that I am not convinced. 



Formerly when I was inclined to lay much stress on protection 

 as accounting for the duller colours of female birds, it occurred 

 to me that possibly both sexes and the young might aboriginally 

 have been equally bright coloured ; but that subsequently, the 

 females from the danger incurred during incubation, and the 

 young from being inexperienced, had been rendered dull as a 

 protection. But this view is not supported by any evidence 

 and is not probable ; for we thus in imagination expose during 

 past times the females and the young to danger, from which it 

 has subsequently been necessary to shield their modified 

 descendants. We have, also, to reduce, through a gradual 

 process of selection, the females and the young to almost exactly 

 the same tints and markings, and to transmit them to the 

 corresponding sex and period of life. On the supposition that 

 the females and the young have partaken during each stage of 

 the process of modification of a tendency to be as brightly 

 coloured as the males, it is also a somewhat strange fact that the 

 females have never been rendered dull-coloured without the 

 young participating in the same change; for there are no in- 

 stances, as far as I can discover, of species with the females dull 

 and the young bright coloured. A partial exception, however, 

 is offered by the young of certain woodpeckers, for they have 

 " the whole upper part of the head tinged with red," which 

 afterwards either decreases into a mere circular red line in the 

 adults of both sexes, or quite disappears in the adult females. 12 



Finally, with respect to our present class of cases, the most 

 probable view appears to be that successive variations in 

 brightness or in other ornamental characters, occurring in the 

 males at a rather late period of life have alone been preserved ; 

 and that most or all of these variations, owing to the late period 

 of life at which they appeared, have been from the first trans- 

 mitted only to the adult male offspring. Any variations in 

 brightness occurriDg in the females or in the young, would have 



12 Audubon, ' Oruith. Biography,' also the case before givsn of Trulo- 

 rol. i. p. 193. Macgillivray, 'Hist, picus carlotta. 

 Brit. Rirds ' vcl. iii. p 85. See 



