262 Observations on Moulting. 



sufficiently borne out by appearances, but which the following 

 observations will serve to qualify very considerably. At the 

 time this species first appears in the London markets, towards 

 the close of autumn, it will be found that all of them are in 

 deep moult, pushing forth abundance of white feathers ; but, 

 during the whole winter, it would be in vain to search for 

 any appearance of a change of plume. The wing primaries, 

 which, at first, have more or less colour, are gradually bleached 

 by the cold weather ; and I perceive that, in the present very 

 protracted season, the black on the tail feathers, and black 

 shafts to the quills, which have been supposed to be perma- 

 nent, have, at length, yielded to the continued severity of the 

 season ; many of the Lagopus saliceti (a species brought most 

 abundantly from Norway) now exhibiting the shafts to the 

 quills completely whitened, and some of them having also the 

 outer caudal feathers more or less blanched ; this change com- 

 mencing at their base, and proceeding outwards. These birds 

 will now very shortly disappear, so that their vernal change 

 cannot be studied in the markets : but, that an actual renewal 

 of the feather does take place in spring, is conclusively shown 

 by some interesting specimens of the British species killed on 

 the 12th of May, forming part of the beautiful collection of 

 Mr. H. Doubleday. The examples alluded to are still in 

 thorough moult, but have renewed the greater portion of their 

 feathers ; though it is remarkable that their wings continue the 

 same as in winter, as is the case with every summer specimen 

 of the ptarmigan which I have hitherto inspected. They lose, 

 at this time, the very dense feathering to the tarse. 



But, to return from this digression to the ducks, it will be 

 observed, that, in the latter, a varying amount of change of 

 colour in the old feathers is a most ordinary concomitant of 

 the assumption of the mature plumage by a moult; and the 

 formerly disputed fact, therefore, is thus demonstrably esta- 

 blished, that, as the secretions which colour the growing 

 feathers also tinge those which are about to be renewed, a 

 circulation (evidently nutrimental ; for, when a bird is ailing 

 or ill fed, the consequences soon appear in their diminished 

 lustre) must, consequently, obtain in feathers, even to the ex- 

 treme period of their remaining attached ; so that the hypo- 

 thesis is unsupported by evidence which ascribes the moulting 

 of a bird to the same cause which has been erroneously sup- 

 posed to bring about the fall of a leaf; namely, that the 

 pores through which the fluids circulate become gradually 

 obstructed, and that it consequently dies, and falls off. 



It would be easy to disprove the same notion by reference 

 to other facts. A snowfleck (Plectrophanes nivalis) which I 



