Poppelwell. — A Pure-white Form of Anas superciliosa. 145 



Art. XVI. — On a Pure-white Form of Anas superciliosa Grnel. 

 By D. L. Poppelwell. 



[Read before the Gtago Institute, 4th August, 1914.] 



Albinism in a greater or less degree is a not uncommon phenomenon among 

 New Zealand birds. The occurrence, however, of a pure-white form of 

 the common grey duck (Anas superciliosa) is of sufficient interest to justify 

 its being put on record. 



Already several specimens of this species showing partial albinism and 

 other variations have been recorded. Dr. Buller, in vol. 7 of the "Trans- 

 actions of the New Zealand Institute," at p. 224, mentions a case of partial 

 albinism, but seems to think that the specimen was possibly a cross with the 

 common domestic duck. He has also, in the second edition of " Birds of 

 New Zealand," mentioned several cases of partial albinism, and states that 

 his son reported having seen a pure albino in a wild state. The specimen 

 was not, however, procured. Mr. W. W. Smith* also describes several 

 aberrant forms of variation tending to albinism. Mr. T. W. Kirkf records a 

 similar instance in the case of the brown duck (Elasmonefta chlorotis). 



The specimen that I have now set out to describe was shot by Mr. George 

 Moffatt on the 21st June, 1914, at Cattle Flat, on the Mataura River. From 

 what he tells me, it was associated with a flock of grey ducks, and had been 

 seen several times by him. It was a good flier, and, except for colour, was 

 not distinguishable from its associates, its flight and habits being the same. 

 Immediately on its receipt by me I sent it to Dr. Benham, who agreed 

 that it seemed to be an albino form of Anas superciliosa. He has since 

 kindly sent me formal measurements of the bird, which are sufficientlv 

 near to those recorded by Buller to make identification practically certain. 

 The following are the measurements taken : — 



Inches. 

 Total length from tip of beak to base of tail-feathers. . 20 

 Length of wirig-quills . . . . . . . . 10 



Length of bill along edge of upper mandible . . 2-25 



Length of bill along edge of lower mandible . . 2-375 



Length of tarsus . . . . . . . . 1-75 



Length of mid toe and claw . . . . . . 2-5 



The bird, on dissection, has proved to be a male. Its plumage through- 

 out is pure white ; eye, dark brown ; legs and bill, yellow. In point of 

 size and shape it differs in no way from the typical wild grey duck. This 

 interesting specimen is in good condition, and has been stuffed and mounted. 

 The owner has generously decided to present it to one of the public museums 

 of New Zealand. For some time at least, if not permanently, it will be 

 deposited in the Otago Museum. 



Note. 



Shortly after the above paper was read Dr. Benham kindly sent me 

 the following communication which he had received from Mr. W. 0. Kemp- 

 thorne, of " Redmount," Key, via Lumsden. As the letter affords a 



* " On New Zealand Ducks," Trans. N.Z. Inst,, vol. 29, 1897, p. 252. 

 t " On some Additions to Birds in the Colonial Museum," Trans. N.Z. Inst., vol. 13, 

 p. 235, 1881. 



