200 Proceedings of the Royal Physical Society. 
XXV.—Notes on the Habits of the Rhea. By A. Pride. (Communicated 
by Professor J. Graham Kerr, F.R.S.). 
(Read 22nd February 1915. MS. received 22nd February 1915.) 
At the beginning of April, in the Paraguayan Chaco, the Rhea begins to 
boom, an indication that the mating season has commenced. To effect the 
boom the male bird draws himself up to his full height, ruffles out his 
neck feathers and, with beak closed, apparently sends the sound through 
his nostrils. The “boom” when heard close to the bird sounds ridiculously 
small and weak compared with its effect at a distance. 
The appearance of the Pleiades in the middle of June, just before day- 
break, is the sign which guides the Indian in his expectation of Rheas’ eggs. 
The announcement of the constellation is usually accompanied with the 
information, ‘we shall soon have Rhea eggs now.” But early in May I 
have taken the eggs, and as late as December they have been brought to 
me; but at the latter time one must beware of their condition. Ten eggs in 
a nest is a very usual number; the largest number I have seen taken was 
twenty-seven. These were all put together by the Indian who found them 
and cooked in a big pot, but a report ike a small cannon announced that 
one at least had “failed.” One of the greatest enemies of the Rhea’s nest 
is the black-maned wolf which wanders solitary over the country, and 
which, finding a nest, puts the parent bird on the unemployed list for 
the rest of the season. 
The parent bird has various calls to its chicks to warn them of danger. 
When they are very small he utters one which causes them to take up 
prone positions on the ground with their little necks stretched out. Their 
coloration at this stage is almost the same as that of a “partridge” 
(tinamou), and as long as they le quiet they are very difficult to detect. 
They seem incapable however of so remaining, and soon begin to whine 
for the parent, which has run off. The monotonous whine is synchronous 
with the downy stage of the chick and ceases when the feathers appear, 
When kept in captivity the chicks are interesting little creatures as they 
go whining round the sides of the house stalking flies and mosquitoes on 
the wall. Even when their stalk is successful a jubilant note never replaces 
the petulant dissatisfied whine. During the first few months of their lives 
the birds consume an enormous amount of dirt and small lumps of sun- 
baked clay, doubtlessly case-hardening their stomachs for future years, 
when they swallow prickly pears whole and suffer no irritation from the 
spines. 
