High ambient temperature decreases eggshell thickness in Zebra Finches

Avian females can alter nest-site selection and breeding behaviour in response to changes in ambient temperature. However, whether females alter eggshell characteristics in response to high ambient temperature is underexplored. To fill this gap, wild-derived and domesticated Zebra Finches were bred at temperatures of 18 °C and 30 °C or 35 °C. Here we show that eggs from finches bred at 18 °C and 30 °C had similar characteristics, but females exposed to 35 °C laid eggs that were significantly thinner compared with the 18 °C group. These data suggest that a temperature that is ecologically relevant to the species in the arid zone of Australia can influence eggshell thickness, which is one of the important factors for hatchability in birds.