Drivers of female reproductive failure in the hihi, Notiomystis cincta.

Reproductive failure is costly for individuals, representing a waste of energetic investment and fitness potential. This is particularly true for females, who typically invest more heavily in reproduction than males, producing larger and more energetically costly gametes than males. Despite this, reproductive failure is commonplace across taxa. This thesis addresses the proximate and ultimate drivers of female reproductive failure in a threatened bird, the hihi (Notiomystis cincta). The hihi is endemic to New Zealand and has undergone multiple genetic bottlenecks due to the impacts of invasive predators and habitat loss. On average, 28% of eggs fail to hatch in the focal study population. In this thesis I focus primarily on the early stages of reproduction, including fertilisation, clutch size, and embryo development, and investigate how these are influenced by genetics, demographics and ecology.