30 0 ?i the Breeding Habits of Heck's Curassow.


conversely that the cessation of incubation and of family cares

act as a stimulus to the organs concerned in egg-formation, pro¬

vided that the time of the year be favourable. Similarly the breeding

of the birds in 1906 and 1908 and their sterility in 1907, under

the conditions mentioned above, show that what is true, if true it

be, of incubation, is no less true of nidification. The two indeed

apparently influence the hen in a manner analogous to that pro¬

duced upon some female mammalia by lactation. But the intimate

physiological connection between lactation and reproduction

in mammalia brings this phenomenon within the scope of our

comprehension. Nidification and incubation on the contrary are

merely manifestations of particular instincts; they are occupa¬

tions followed in obedience to certain innate promptings and, as

such, fall into the category of psychical not of physiological

phenomena. Yet if the supposition be correct that the repro¬

ductive activities are affected by these occupations, the fact con¬

stitutes a problem in physiology which, so far as I know, cannot

be quite matched in the mammalia, although an approach to it is

seen in the internal effects produced by the emotion of fear or in

the stimulus to salivation supplied by the sight of appetising

food.


I have merely cited nidification and incubation as possible

causes in determining the maturation of eggs, because the

Curassows furnished the data. I do not doubt that other factors,

apart of course from food and bodily health, produce the same

apparent results, The question, however, is clearly one for in¬

vestigation ; and perhaps some of my avicultural colleagues may

be induced to record their experiences and opinions on the sub¬

ject so that the suggestions above put forward may be finally

refuted or confirmed. That the question at issue is worth dis¬

cussion must be admitted ; and I have ventured to draw attention

to it in the pages of our magazine largely because it brings us

face to face with physiological possibilities of importance outside

aviculture and ornithology, and shows that the cult of birds may

have a value beyond the gratification of the tastes and interests of

those who practise it, beyond even the new facts in natural

history it is constantly revealing.



