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J. Delacour—Rheas



the quality of the grass, being sufficient for one bird with the addition

of some other food whenever necessary. They squat on the ground at

night, their necks pressed in their backs, often settling down at the foot

of a tree on the opposite side to the wind, if it is strong. In the spring,

fights take place amongst cocks, but they are always harmless and

never last long, a hierarchy between the stronger and weaker birds

being soon established. Rheas do not pair up, the females being often

fertilized in turn by different males. The master cock of the flock

usually makes the first nest: a deep scrape in the ground where he

gathers a few twigs and feathers together. Several hens come and lay

near the nest, in which the cock soon starts sitting, squatting very low.

He brings the eggs into the nest, sometimes from fairly long distances.

When he has gathered a sufficient number, usually from ten to fifteen,

another male starts sitting and attracts the laying hens, and so on

till they have finished laying and there are no more males available.

Owing to various causes, the number of eggs in one nest may sometimes

be very large, and I have known of a cock to sit on more than thirty,

a fair proportion of which duly hatched out.


Common Rheas’ eggs are rather elongated in shape and, when

freshly laid, of a greenish yellow’ colour, changing into creamy white

later on. The cocks alone perform the whole duty of incubation,

getting up every day once or twice to feed and drink, the hens taking

no interest in the nest after they have laid their eggs, which take from

forty-two to forty-five days to hatch ; the nesting season in Europe

lasts from April till August.


Darwin’s Rheas’ eggs are slightly smaller and much brighter,

their colour being a deep yellowish green ; their incubation period

is from forty-four to forty-six days and they are laid very early in our

climate, often at the beginning of March.


Difficulties may arise during the incubation ; sometimes a cock

is disturbed by another one who wants to sit with and close to him and

robs him of his eggs, wdiich, as a result, are often broken in the process.

At other times, hens or young non-breeding birds will peck and smash

eggs while the cock is away feeding. The best way to avoid such troubles

is to build up a temporary fence of wire netting round the nest, long

enough to provide the sitting bird wfith a sufficient run to w r alk a little



