Lack's principle

Birds lay only as many eggs as they will be able to provide for.
If there are too many mouths to feed, fewer young will survive, reducing the parents' reproductive fitness.

Lack's principle, proposed by the British ornithologist David Lack in 1954, states that "the clutch size of each species of bird has been adapted by natural selection to correspond with the largest number of young for which the parents can, on average, provide enough food".[1] As a biological rule, the principle can be formalised and generalised to apply to reproducing organisms in general, including animals and plants. Work based on Lack's principle by George C. Williams and others has led to an improved mathematical understanding of population biology.

  1. ^ Lack, David (1954). The regulation of animal numbers. Clarendon Press.