Clutch (eggs)

In birds, destruction of a clutch by predators (or removal by humans, for example the California condor breeding program) results in double-clutching.

The technique is used to double the production of a species' eggs, in the California condor case, specifically to increase population size.

It may also differ within the same species due to many factors including habitat, health, nutrition, predation pressures, and time of year.

In birds, clutch size can vary within a species due to various features (age and health of laying female, ability of male to supply food, and abundance of prey), while some species are determinant layers, laying a species-specific number of eggs.

In birds, ornithologist David Lack carried out much research into regulation of clutch size.