472 Mr. J. licwis Bouhote on Moult 



or early summer, representinj;' iiulividuals of a dift'ereiit age, 

 will often show a nearly conii)lotc scries of intcrgrades 

 between the two styles of plumage, and there will, of course, 

 be no signs of a monlt." 



I understand from this that Mr. Stone only recognizes 

 intergradcs on different individuals ; but if he were to study 

 the Limicoiffi, whicli avowedly he has not done, the intcr- 

 grades would be found on the same individual. If, further- 

 more, he would extend his observations to birds in con- 

 finement, he would notice that the intcrgrades on any one 

 individual do not remain constant, but that, " although there 

 were no signs of moult," the int(!rgrades would gradually 

 give place, until the bird had assumed its full and complete 

 plumage. 



There is no need to lay down a hard-and-fast law for all 

 kinds of birds. In the Corncrake, for instance, there can be 

 no change of pigment, since blue is not a pigraent-colonr. 



In the Linnets and Redpolls, although the change is from 

 brown to red, tio further pigment is introduced when once 

 the feather is formed. The evidence on this point is as 

 follows ; — In confinement, through some cause as yet un- 

 known, birds of this genus become yellow instead of red 

 in their full dress. If a bird be taken wild in autumn in 

 its brown plumage, it will become red the following spring ; 

 on the other hand, if it should be taken in July, before 

 moulting, it will become yellow in the following spring. 

 This shows that in this case the red pigment is probably 

 de})Osited in the feather when formed in the autumn. 



T^o sum up briefly, it appears, so far as we are at present 

 able to judge, — 



I. That in some cases, e.g. Crex and Colymbus, a moult 



takes place entirely independent of colour-change. 



II. That it does not follow that because a bird is moulting 



a colour-change in individual feathers, be tliey old or 

 new, is thereby excluded. 



III. That in the same bird, and in the same feather-tract, 

 a different plumage may be assumed, partly by moulting, 

 and partly by a colour-change in the old feathers which 

 are not cast. 



