7 RHEIDAE 31 
feathers of the wings and back. Hens are not so dark, and Mz. 
Hudson says! that in R. darwint the young are dusky grey 
and are hatched with the 
legs feathered to the toes. 
Rheas are shorter than 
Ostriches by about a couple 
of feet, R. americana being 
the largest form; the feathers 
are much rounded, broad, 
and very soft. Fossil re- 
mains occur In the Upper 
Tertiary or quite- recent 
deposits of South America. 
The members of this 
family find their favourite 
haunts on the treeless flats 
of the Argentine pampas, 
the scrub-covered plains of 
Patagonia, or the dry open 
Sertoés of Brazil, where 
thei acute vision enables 
them to detect the approach 
of enemies from afar. 
Small flocks of from three 
to seven individuals are met 
Malina Gerbalme Seasons, and Frc. 9.—Nandul' “Rhed-ainericanas® <2 
parties of twenty or thirty 
at other times—often with deer or guanacos—so it would appear 
that, as in the case of the Ostrich, larger companies are formed 
after the young are able to provide for themselves. The birds 
become exceedingly tame when not molested, but when danger 
threatens they run at great speed, doubling upon their pursuers 
constantly, or crouching down among bushes or other cover, if they 
think they can escape observation. In the latter case they will 
he closely until almost trodden upon, and may be shot before they 
rise by the hunter who cautiously approaches their hiding-place, 
as the head is usually visible above the surrounding vegetation. 
When moving at full pace the wings have normally a somewhat 
drooping position, but they are raised alternately above the back 
1 Argentine Ornithology, ii. 1889, p. 220. 
