The object of this plan is that if the bird is killed, or is made to give up sitting by bad weather, the eggs are nevertheless not injured, but are merely passed on to be divided amongst other birds.
It has been said that there is no advantage in this plan, but one cannot help thinking that only lazy keepers and their friends who sell game foods would say so.
The argument is that the nests are not in danger from foxes until just at the time of hatching. It is said that the birds lose their scent when incubating, and that only when the chicks break the shell is there any scent from the nests. As a matter of fact there is very little scent from breeding birds whether they are sitting or laying, but to say there is none, and that foxes cannot find them, is a total mistake.
Nests are taken by dogs and foxes, and by hedgehogs and rats, at all times of the incubating period. If the birds gave out as much scent as they do at other periods, there would be _no_ nests left in a fox country. But nature and the birds, between them, do defeat the foxes and the vermin in a fair proportion of cases. It has been affirmed that incubating alters their system, and that the scent that before passed out through the skin passes out with the excreta when the birds incubate. That is to say, that there is a total change of system brought about by the change of instinct. The stronger scent from the excreta of sitting birds has been advanced as a proof of this. The author will not discuss this theory or deny it, but he is certain that the whole loss of scent can be accounted for in another way. There is perhaps a change of scent in breeding creatures. To explain this, in a doubtful way, it has been affirmed that in gestation the superfluous essence of a beast finds a use in being drained by the blood to the embryo.