AVIFAUNA OF LAYS AN, ETC. 



273 



younger individuals, as the already-mentioned very young bird (with the wing-feathers 

 only half- grown) has them also less bold. Some variations in the gloss of the speculum, 

 the borders of the latter, and the colour of the under wing-coverts are mentioned 

 above. The total length of the females is about to 17^ inches, wing 8*5 to 9, 

 tail 3 to 3-3, culmen 16 to T8, tarsus 15. 



Young in down. Almost exactly like the young in down of Anas boschas, but the olive tint 

 is apparently more variable and generally less intense. 



The Sandwich-Island Duck has only one somewhat near ally, i. e. Anas laysanensis, Eothsch., 

 from Laysan. This latter, however, can generally be distinguished by the white ring round 

 the eye, its smaller size, more regularly barred rectrices, always spotted axilliares, more 

 reddish colour, and other characters. In its curled-up central tail-feathers it resembles 

 A. boschas, and this singular character is also developed in A. laysanensis, but in no other 

 Duck besides. 



There can be absolutely no doubt that Dr. Sclater's name of wyvilliana must be accepted 

 for the Sandwich-Island Duck, as Bonaparte's name of sandwichensis was not accompanied 

 by any description. 



The " Koloa Maoli," or " Koloa," is probably an inhabitant of all the Sandwich Islands, 

 where it most likely breeds wherever it finds suitable localities. 



After the breeding-time they keep in flocks. On the lake on Niihau, Palmer observed 

 large flocks, sometimes probably not less than a hundred together. 



In habits and nidification this Duck does not seem to differ from Anas boschas. 



It is evidently distributed all over the islands. Palmer sent me a large series from 

 Kauai, Hawaii, Niihau, and Oahu. The nestlings were taken on May the 6th at Waialua, 

 Oahu. 



