Parental Effects and Climate Change: Will Avian Incubation Behavior Shield Embryos from Increasing Environmental Temperatures?

A major driver of wildlife responses to climate change will include non-genomic effects, like those mediated through parental behavior and physiology (i.e., parental effects). Parental effects can influence lifetime reproductive success and survival, and thus population-level processes. However, the extent to which parental effects will contribute to population persistence or declines in response to climate change is not well understood. These effects may be substantial for species that exhibit extensive parental care behaviors, like birds. Environmental temperature is important in shaping avian incubation behavior, and these factors interact to determine the thermal conditions embryos are exposed to during development, and subsequently avian phenotypes and secondary sex ratios. In this article, we argue that incubation behavior may be an important mediator of avian responses to climate change, we compare incubation strategies of two species adapted to different thermal environments nesting in extreme heat, and we present a simple model that estimates changes in egg temperature based on these incubation patterns and predicted increases in maximum daily air temperature. We demonstrate that the predicted increase in air temperature by 2100 in the central USA will increase temperatures that eggs experience during afternoon off-bouts and the proportion of nests exposed to lethal temperatures. To better understand how species and local adaptations and behavioral-plasticity of incubation behavior will contribute to population responses to climate change comparisons are needed across more avian populations, species, and thermal landscapes.