II4 ORNAMENTAL WATERFOWL. 
Egg.—Ivory-white, somewhat round. Incubation, twenty- 
eight to thirty days. 
Nest Down.—Long ; centre ashy-grey, tips nearly black. 
SOUTHERN RED-BILLED WHISTLING DUCK. 
(Dendrocycna discolor ). 
This Tree Duck was received by the Zoological Society 
in 1874 from Parad, in South America. Messrs. Sclater and 
Salvin state this form is easily distinguished from Dendro- 
cycna autumnalis by the upper portion of the back being grey 
instead of chestnut, while the breast is of the same colour. It 
inhabits the northern parts of South America. 
The specimens of Dendrocycna discolor in the Zoological 
Gardens were presented by Mr. E. Harper, in July, 1905, and are 
new to the collection. Presumably these are the same species 
which were received by the Zoological Society in 1874, and at 
that time differently named. 
This Tree Duck, called by Buffon ‘the Whistler with the 
red beak and yellow nostrils,” is found in Columbia and Guiana, 
together with parts of Peru and Brazil, and is stated by Sclater 
and Salvin to be distinguishable at a glance from the Central 
American form, by its grey upper-back and chestnut-brown 
lower part. In this southern form also, the breast is grey instead 
of chestnut as in D. autumnaks. 
BLACK-BILLED TREE DUCK OR WHISTLING DUCK. 
(Dendrocycna arborea). 
This Tree Duck inhabits the West Indies and Bahama 
Islands, and is occasionally for sale in this country, realising 
from £3 to £4 the pair. Mr. Gosse states that these birds 
