50 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
end of the inner secondaires and the whole underpart of the body white as in the 
adults. j 
This form, belonging to the Aru islands, has not been found before except in 
the North Territory of Australia. Only one specimen was seen in a pool of water 
8 miles from the coast at Beagle bay. 
Nycticorax caledonicus Gm. 
Math. handl. n:r 210. JF ad., 222 ad. Nooncanbah, Fitzroy river "5/;> 1910; '"/1, S/P1917, moult. 
Moulting. — The male is in full spring plumage and must have finished its 
moulting pretty recently. The others are in slight moulting (on the breast), and the 
long plume is growing out, only a third or fourth part as long as in the male. At 
first the point of this feather is black and brown, but later on it is abraded. Com- 
mon at Fitzroy river. 
Order Anseriformes. 
Fam. Anatidee. 
Dendrocygna arcuata HOoRrsF. 
Math. handl. n:r 222. 2 SSI ad., 1 2 ad. Hot Spring, Georges range ?/2 1911, moult. 
Besides Fitzroy river it was not infrequently seen at Mowla Downs after the 
November rains. At Sunday Island I have not seen it. 
Dendrocygna eytoni GouLp. 
Math. handl. n:r 223. 9 ad., Nooncanbah, Kimb. ?”/12 1910, moult.; J ad., Hot Spring, ibid. ?/2 1911, 
moult. 
KE cological. — After the rains this wild duck, like the former species, appeared 
rather frequently in the neighbourhood of Mowla Downs. It was first seen in small 
flocks. The l4th of Dec. (1910) its nest was found in the grass, and 8 new-laid 
eggs in it. Was met with also at Fitzroy river in Dec. (WIiDELL) but not at Sunday 
Island. 
Anas superciliosa GM. 
Math. handl. n:r 226. 3 SSI ad. Hot Spring, Fitzroy river 3/:, !!/s, 11/5 1911, moult. 
No. 3 on the lower part of the neck a strong rufous tint, going down the 
breast. It is caused by the brown rufous edges of the new feathers. These edges 
seem to be bleached later on. 
