Abstract
The volume of male eggs in Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) was slightly larger than that of female eggs in every year of a 5-year study. The volume difference was highly significant (P < 0.01) when data for all years were combined. Male nestlings also grew faster than female siblings. Natural history observations on adults suggest that reproductive success is more variable in male than in female Whitecrowned Sparrows. Taken together, these data are consistent with facultative manipulation of offspring sex as proposed under the Trivers and Willard hypothesis (1973). In avian species it may be necessary when testing this hypothesis to consider the relationship between sex and parental investment for individual offspring rather than focusing solely on differences between broods.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
