170 DENDROCYGNA ARBOREA 



Zappey (1905) found them carefully concealed in the cienagas (swamps) during the 

 day, leaving, toward dusk, to feed on the fruit of the royal palms. These habits are 

 uniform and have been noted by numerous observers in the West Indies. A curious 

 trait is mentioned by English (1916), who says that they seem to wander a good deal 

 during the night and by no means infrequently alight on the galvanized iron roofs 

 common on Grand Cayman, mistaking them perhaps for pools of water. Dr. L. C. 

 Sanford tells me that he never saw them on Andros Isle during the day, but only 

 on moonlight nights when they came into a small fresh-water pond to feed. 



Flight. Like related species the Black-billed Tree Ducks fly steadily, but with- 

 out the speed of true ducks. 



Gait. These birds walk slowly and with stately carriage, the necks stretched 

 upward, alert and noting every danger; at other times the neck is gracefully bent. 

 When wounded they are particularly difficult to secure for they run with great 

 rapidity, outstripping a man if they have only been winged, unless, as Gosse (1847) 

 puts it, "he be very nimble." 



Swimming, Diving, and Perching. They are rarely seen in the open water, where 

 they are, no doubt, exposed to the attacks of lurking crocodiles. Whether or not they 

 ever dive I cannot say, but in general, Tree Ducks acquire this habit in captivity. 

 As to perching, they are frequently seen in high trees, and are partial to palm trees. 



Association with other Species. Over the entire extent of its range there are 

 comparatively few other ducks and no geese. A few Black-bellied Tree Ducks may 

 occur in Jamaica, and the Bahama Duck is a scarce resident throughout the West 

 Indies. The northern migrants of other species occur only irregularly in any num- 

 bers. It is, therefore, unlikely that the present species has anything to do with other 

 ducks. 



Voice. One of the older writers (Gosse, 1847) referred to the peculiarly shrill 

 whistling notes uttered during the crepuscular flights to and from the feeding 

 grounds, and also when alarmed, and likened them to the sound produced by blow- 

 ing forcibly over "the pipe of a draw key." Other observers describe the note as an 

 agreeable whistle, and Bangs and Zappey (1905) compare it with that of the Caro- 

 lina Duck. Besides the whistling flight note the birds have a feeding call which 

 Gundlach (1875) describes as monotonous but not loud. The voice is doubtless the 

 same in both sexes and the syrinx, a symmetrical, diamond-shaped pouch with a 

 shallow keel down its middle, is also the same in the two sexes (Newton, Ibis, ser. 1, 

 vol. 1, p. 366, 1859, plate). The whistled note can be heard at a great distance and 



