on the Breeding Habits of Heck's Curassozv. 29


4 The eggs, two in number, are white and rough.


5 The incubation period is twenty-eight days.


6 The wings of the newly hatched young have distinct flight


feathers which grow very rapidly.


7 The chicks leave the nest and follow the mother to the ground


the first day after hatching.


8 She broods them on the ground for a few nights and at


intervals during the day. After this they spend the nights

perched by her side on a branch well above the ground,

reaching their position by climbing.


9 They feed at first upon insect food, and afterwards take to


the diet of their parents.


10 For several weeks they do not peck food from the ground but


take it from their mother’s beak. At ten weeks old they

feed themselves and are also fed by her.



One or two circumstances mentioned in the above

given account give me the excuse to introduce a subject

connected with bird-breeding which is, I think, of the greatest

scientific interest. The Curassows in question furnished an

admirable illustration of a phenomenon, familiar no doubt to

most aviculturists, but one which is none the less remarkable for

all that. I refer to the wonderful extent to which the repro¬

ductive activities of birds appear to be influenced, both in the

way of suppression and stimulation by what seem to us to be

trivial factors in their environment, factors indeed which the

inexperienced would declare to be quite inadequate to produce

the results that apparently follow from them. For instance, the

pair of Curassows bred in 1906 and in 1908 when a suitable site

and nesting materials with which to build were at hand. In


1907 they evinced no sign of even wishing to breed when these

desiderata were not available. Again when the first two eggs of


1908 were smashed, the loss was made good in a few days ; and

no one will suppose that the second lot would have been pro¬

duced but for the accident which robbed the birds of the first

clutch. This suggests that incubation acts upon the organisation

of the hen in some way adverse to the development of eggs, and



