Summary: Garcia-Fernandez et al. (2010)

Eggs constitute most of the maternal investment in precocial birds as parents do not feed young post-hatching. The embryo and chick development are influenced by maternal testosterone in the yolk. Testosterone is deposited in eggs by females in response to the environment experienced during the laying period, which includes the quality of the mate. Garcia-Fernandez et al. (2010) assessed the relevance of female mate choice on egg characteristics in the grey partridge Perdix perdix. Females were allowed to choose between males in choice trials and were then mated with either preferred or non-preferred males. They found that eggs from both groups did not differ significantly in mass, but females mated to preferred males produced eggs with higher testosterone levels. They suggest that partner attractiveness is important in the transfer of maternally derived egg components.