A Ground-Nesting Galliform's Response to Thermal Heterogeneity: Implications for Ground-Dwelling Birds

PLoS One. 2015 Nov 30;10(11):e0143676. doi: 10.1371/journal.pone.0143676. eCollection 2015.

Abstract

The habitat selection choices that individuals make in response to thermal environments influence both survival and reproduction. Importantly, the way that organisms behaviorally respond to thermal environments depends on the availability and juxtaposition of sites affording tolerable or preferred microclimates. Although, ground nesting birds are especially susceptible to heat extremes across many reproductive stages (i.e., breeding, nesting, brood rearing), the mechanistic drivers of nest site selection for these species are not well established from a thermal perspective. Our goal was to assess nest site selection relative to the configuration of the thermal landscape by quantifying thermal environments available to a ground-nesting bird species inhabiting a climatically stressful environment. Using northern bobwhite (Colinus virginanus) as a model species, we measured black bulb temperature (Tbb) and vegetation parameters at 87 nests, 87 paired sites and 205 random landscape sites in Western Oklahoma during spring and summer 2013 and 2014. We found that thermal space within the study area exhibited differences in Tbb of up to 40°C during peak diurnal heating, resulting in a diverse thermal landscape available to ground-nesting birds. Within this thermally heterogeneous landscape, nest sites moderated Tbb by more than 12°C compared to random landscape sites. Furthermore, successful nests remained on average 6°C cooler than unsuccessful nests on days experiencing ambient temperatures ≥ 39°C. Models of future Tbb associated with 2080 climate change projections indicate that nesting bobwhites will face substantially greater Tbb throughout the landscape for longer durations, placing an even greater importance on thermal choices for nest sites in the future. These results highlight the capacity of landscape features to act as moderators of thermal extremes and demonstrate how thermal complexity at organism-specific scales can dictate habitat selection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Physiological
  • Animals
  • Body Temperature*
  • Ecosystem*
  • Galliformes / physiology*
  • Heat-Shock Response
  • Nesting Behavior*

Grants and funding

Funding for this research was provided by the Oklahoma Department of Wildlife Conservation grant # F11AF00069, to CAD RDE and SDF. The Oklahoma Cooperative Fish and Wildlife Research Unit administered funding and provided logistical and administrative support. Further support was provided by the Oklahoma Agricultural Experiment Station. Some of this manuscript is based on work supported by the National Science Foundation under grant no. IIA-1301789 and grant no.1413900 to SDF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.