Maternal testosterone and offspring sex ratio
Sex allocation theories claim animals should adjust the sex of their offspring in response to environmental conditions, to maximise their lifetime reproductive success. Avian females can manipulate offspring sex, by influencing which sex chromosome is retained in the ovulated oocyte and which is discarded. As yet, the mechanism for sex allocation is unclear, despite wide theoretical and empirical support. This research investigates the potentially mechanistic role of circulating testosterone in laying hens. Ultimately, we hope to use this as a tool to manipulate offspring sex ratios, which would be an important development for conservation and in the poultry industry.
Night-time light pollution
As humans encroach ever more on different habitats, the animals living in these areas must adapt to a brightening night sky. Essentially, they are experiencing a simulation of longer days, which has previously been shown to affect immune function, behaviour, and reproductive cycles. This study investigates the effect of artificial light on stress hormones and reproductive timing, using the Eastern bluebird as a model species.
Urbanisation, diet, and stress
Some birds are able to readily adapt to human-modified environments; the White Ibis is one of them. This project investigates how the diet and immune response of the White Ibis in Florida is affected by moving from rural to urban habitats. Further, how might their endocrinological state be affected, particularly circulating stress hormone concentrations, and how is reproduction affected?
A secondary project investigates the effect of human activity on nestling corticosterone responses in Eastern bluebirds.
See also the Hernandez Lab
Check out this hilarious video about the Australian White Ibis (NB: lots of swearing!)