Nutritional constraints on egg production in birds

Abstract

The production of eggs can make a major nutritional demand on a female bird. The scale of the required investment varies between species, depending on the size of each egg and the number of eggs laid. For large species, where egg weight is a small proportion of female body mass, the investment in the egg is small, but in some passerines the female will lay a clutch that weighs more than her own body weight. This requires a substantial investment of both energy and nutrients. Robbins (1981) estimated that the daily cost of egg production to wild birds varied between species from 37 % to 216 % of normal daily energy metabolism and from 86 % to 230 % of daily protein requirements.