Spring Plumage ivithout a Moult. 455 



colour aud the new ones assimilate themselves^ during their 

 growth^ to the old feathers, which are also changing. As in 

 the case of nearly all changes to summer plumage, the feathers 

 of the lower breast, lower back, or tail are not cast. 



In method No. III. we see the most remarkable change, and 

 this being of the type of which Mr. Allen so strenuously 

 denies the existence, it is, perhaps, the most interesting : 

 namely, the case where the bird assumes its summer dress by 

 means of a recoloration of the feathers, in which both altered 

 forms and colours take place. A few feathers are, however, 

 generally cast on the neck and breast, which are replaced 

 by new summer ones. 



In this order perhaps the best examples are to be found in 

 the large class of Waders : f I'om which I take, as an example, 

 the Sanderling [Calidris arenaria). Illustrations are given 

 (Plate X. figs. 8-12) showing the gradual change of a feather 

 from the back of the neck during the period extending from 

 March to August. 



The Waders are amongst the few birds in which seasonal 

 changes of plumage are practically unaffected by confine- 

 ment. Any regular visitor to the Gardens of the Zoological 

 Society will have noticed how coincidental with wild ones 

 most of the species kept there are in this respect. Even, 

 therefore, supposing we could not believe the evidence of 

 our own eyes, that the feathers undergo their great change 

 without renewal, we have still to get over the fact that 

 old feathers are not cast in the cages in spring in any quantity, 

 whereas a complete moult undoubtedly takes place in autumn. 

 Mr. AUen^s chief argument seems to be that a feather once 

 completed is dead and retains no further power of trans- 

 mitting colour through the quill from the epidermis. Now 

 if this were the case, how is it that we find a feather like that 

 of figs. 9, 10, and 1 1 — feathers which are to be found iu the 

 plumage of the bird during successive months ? According 

 to Mr. Allen the bird would have to renew its feathers every 

 month, which is a manifest improbability. As there can be 

 no reasonable doubt that the same feather goes through the 

 change exhibited in figs. 9 to 13 (because there is no moult 



