1500 The Zoologist — January,,18C9. 



or peiliaps naturally, retain the plumage of the past summer ; or, more 

 likely, tliat they are adult birds that change the winter plumage to that 

 of summer, by the mere addition of new-coloured pigment, and not by 

 moult, as is the case among many other sea-fowl. It may be, though 

 I have no cause for such a supposition, that the supposed distinctive 

 marks of summer plumage, in cases of extreme age, become con- 

 firmed. (See Zool. S. S. 681.) 



In perfect Summer Plumage in October. — October 15. Two adult 

 redthroaled divers passed me on the wing to-day, and, thanks to Eley 

 and his wire-cartridges, one of them fell dead. It was a splendid 

 specimen, and, late as it is, in rich full summer plumage, without any 

 indication of moult, though somewhat faded by age. 



On the Autumn Moult of Adults.— October 28. Shot two adult red- 

 throated divers to-day off Sallhill : they were in very strong moult. 

 No. 1 has very few of the red- and lead-coloured feathers of the neck 

 remaining ; the new feathers in these parts are white, some in the red 

 ]);itch being lightly edged witli gray. The bill is changing from the 

 black of summer to the blue of winter, having at this time a tortoise- 

 shelled appearance from the two colours. The eye still as bright as 

 in summer, brighter than arterial blood-red, but not crimson, like the 

 .sluffers' eyes. Several of the beautiful mane-like feathers arc in the 

 neck still, though the winter feathers in that part are most abundant. 

 The back, scapulars and wing-coverts are half in summer and half in 

 winter. Every old quill-feather is from the wing, and their place sup- 

 plied by the stumps of the new quills, all exactly the same length, 

 showing how uniform and rapid is the moult in this part. Strange to 

 say, in the breast are several feathers quite black, reminding one of 

 the abnormity in colouring so often noticed on the white under side 

 of several flat-fish, particularly the flounder. No. 2 has consider- 

 ably more red feathers in the throat and lead-colour in the neck : 

 in other res])ects it is quite similar to No. 1. Both the primary and 

 secondary quills are all new, all equal in length, about one-third 

 grown, showing that all are lost and all assumed at the same time — in 

 these two birds I might say the same day. The new quill, in the 

 divers, grows from the pen of the old quill; thus in pulling out an 

 old quill in moult time you will pull out the young embryo more or 

 less developed, either as a globule of blood and pigment or a tube of 

 the same matter, so when the young quills have taken root and are 

 ready to come forth they push the old ones out before them. It must 

 be essential to the divers to have the wings of equal strength, pecu- 



