Adaptive Significance of Plasticity in Hormone-mediated Avian Reproductive Behaviors in a Changing Climate

EPA Grant Number: FP917232
Title: Adaptive Significance of Plasticity in Hormone-mediated Avian Reproductive Behaviors in a Changing Climate
Investigators: Kaiser, Sara Ann
Institution: Cornell University
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Global Change


Climate change in north temperate latitudes is causing temporal shifts in the environmental cues organisms use to time breeding events with environmental conditions (e.g., food resources), and this likely will have drastic consequences for the population demographics of migratory birds. Currently, there is little known about whether and how species will be able to respond to these changes. We know that seasonal changes in circulating hormone levels can modulate avian reproductive behaviors that directly influence fitness, but surprisingly little is known about the environmental cues that signal these underlying endocrine mechanisms. To assess the potential for species response to climate change, it is necessary to know the mechanism by which environmental cues such as food and temperature affect endocrine systems and also the extent to which plasticity in the regulated reproductive behaviors is adaptive.


Global climate change may negatively impact populations of migratory birds. As temperatures shift, migrating birds experience adjustments in the timing of leaf-out and peak food resources. These cues may be used to time breeding events with environmental conditions. To assess the potential for species response to climate change, this project examines how temperature and food signal the hormones modulating the breeding behaviors of birds that influence their survival and reproductive success.


I propose to examine the linkage between testosterone and corticosterone and individual adjustments in mating and parental effort by males in response to experimentally manipulated food availability along an environmental gradient. I will simultaneously measure several factors during supplemental feeding that contribute to territory quality and may influence mating and parental effort to isolate the effects of food. I will thus be able to assess the degree of plasticity in male hormonal and behavioral responses to resource conditions and their fitness consequences. The study I propose will integrate genetic and hormone analyses, population demographics of a migratory songbird that has been monitored for 40 years at a site where anthropogenic climate change has had detectable effects, and experimental manipulation of food on individual territories.

Expected Results:

My large-scale experiment is a novel approach that will lead to important insights about the effects of food on mating and parental effort and the adaptive significance of reproductive trade-offs in a changing environment.

Potential to Further Environmental/Human Health Protection:

As human populations and their demand for resources grow, there is an increasing need to monitor the response of indicator species in natural ecosystems to changes in the environment that are causing resource depletion and reducing the ecosystem services provided by species. Understanding the relationship between species and ecosystem stability is essential to the management of natural resources.

Supplemental Keywords:

climate change, birds, hormones, reproductive behaviors, environmental gradient,

Progress and Final Reports:

  • 2011
  • 2012
  • Final