WANDERING TREE DUCK 143 



Daily Movements. Undoubtedly nocturnal in habits, the Wandering Tree 

 Ducks spend the heat of the day in shady places, and at evening fly to their feeding 

 grounds. In North Queensland they come to the coast at night, returning inland at 

 daylight (Robinson and Laverock, 1900). Their whistling notes, heard as they fly 

 about at night are familiar to many naturalists. In the northern parts of Australia 

 they are described by Keartland (North, 1913) as flying "inland on the Mitchell- 

 grass or .Flinders-grass Plains to feed, but towards daybreak they frequent the 

 rivers or lagoons for a bath and a drink, and then cluster on the shady side of any 

 thick bushes to sleep through the day, only moving when disturbed, or to escape 

 the sun." 



Flight. On the wing they are described by Whitehead (Ibis, ser. 7, vol. 5, p. 501, 

 1899) as using their wings — which appear large for a duck — like a heron, but 

 more quickly. There is no reason to suppose that the flight differs from that of other 

 Tree Ducks. But both this species and the Indian Whistling Teal are said by Hein- 

 roth (1918) to have a peculiar projection on the inner web of the most external pri- 

 mary, which gives rise to a loud whistle during flight; but this unusual feather is not 

 so well developed in Dendrocygna arcuata as in Dendrocygna javanica. As a matter 

 of fact the primary in this species is simply notched, leaving two prominent projec- 

 tions, but there is no "thumb" as in Dendrocygna javanica. 



Like their congeners, they sometimes assemble in very considerable companies. 

 From Rockhampton large flocks have been recorded (Ramsay, 1876). At Port 

 Essington, Gould (1865) found vast flocks from September to December. Grabowsky 

 (1885) speaks of flocks numbering ten to fifty in southeastern Borneo, and in the 

 Philippines it is frequently met with in large companies (R. C. McGregor, 1909). 

 The largest flock referred to in the literature is one of three hundred, seen at Bar- 

 ramine Station in Australia (North, 1913). 



Gait. Rogeron (1903) speaking of his captive birds, described them as having a 

 more horizontal posture than other Tree Ducks, with the back somewhat curved. 

 But he says nothing about the gait, nor have I been able to obtain any special in- 

 formation on this point from any source. 



Swimming and Diving. The species is a grass-feeder, is gooselike in its habits, 

 and is therefore more active on land than on water. Grabowsky (1885) describes it 

 as an expert diver, probably referring to its ability to escape when wounded. Finn 

 (1909) states that they dive for food in the London Zoological Gardens, but several 

 species, which never dive in the wild state, have been known to do so when pinioned 

 in enclosures and consequently Finn's remarks are not conclusive. Nevertheless, 

 Heinroth (1918) goes so far as to say that all species (of Tree Ducks) seem to get 

 nourishment "chiefly" by diving. 



