134 DENDROCYGNA BICOLOR 



ring in fairly large flocks in Kordofan, but others, like Sjostedt (1910), never met with 

 large flocks. Judging from the restricted number of references in the literature on 

 African ornithology one is forced to the conclusion that it is, in general, an uncommon 

 bird on that continent. 



Gait. On the ground, like its congeners, this species assumes an upright position, 

 and progresses with an easy anserine walk. It spends much of its time walking and 

 standing on the shore of a pond, as any one visiting a zoological garden may note. 

 This habit has probably resulted from the fact that, like other tropical ducks, it is 

 unable to remain long upon the surface of the water, because of the presence of 

 crocodiles. When out of the water they crowd together, and if disturbed stand up, 

 craning their necks and looking strangely tall on their long, blue legs (P. L. Sclater 

 and Hudson, 1889). When winged they escape by running and springing with ex- 

 traordinary agility (Lawrence, 1874). 



Perching. It is very difficult to make a definite statement as to how much time 

 these birds spend in trees. No doubt the character of the country has much to do 

 with the practice of the birds in this matter, for Hume and Marshall (1879) report 

 them perching a good deal in India, while Baker's (1908) observations are to the 

 contrary. Horsbrugh (1912) speaks of their perching freely in Africa, but then again 

 in Venezuela the birds are said not to frequent the trees at all (Andre, 1904). In the 

 Valle de Mexico they perch, and as a matter of fact chiefly on thin branches (Her- 

 rera, 1881). In California, where they appear for the nesting season, they are almost 

 entirely birds of the tule swamps and irrigated, overflow lands. 



Swimming and Diving. Having never watched these birds, except in confine- 

 ment, I cannot say whether any of their food is procured by diving. I never saw my 

 pinioned specimens dive, nor did they spend much time upon the water. Observers 

 have described them as diving well (Lawrence, 1874; Finn, 1915), but this no doubt 

 refers more to cases of crippled birds attempting to escape than to normal feeding 

 habits. There is every indication that the Tree Ducks as a group are to be con- 

 sidered as surface-feeders and grazers only, although they are known to procure 

 food by other methods, even resorting to trees to obtain fruit. I have never myself 

 observed either this, or the preceding species, tipping up in the water like Mallards 

 or Teal. When wounded, however, they are extremely agile divers, coming to the 

 surface with only the head above water, like a grebe (Lawrence, 1874). 



Association with other Species. The writers on India do not say whether the 

 Fulvous and the Lesser Whistling Teal associate, hence one must assume that they 

 do not. Occasionally in Africa flocks of Dendrocygna bicolor are found mixed with 



