Weissburg et al. Mountain Plover Stage-specific habitat use - Markdown and data files

Factors like habitat structure, food availability, and predation risk have spatiotemporal variation on the landscape, creating tradeoffs between risk and rewards for animals as they use habitat, and these tradeoffs can vary by life stage or breeding stage. We investigated habitat use in the Mountain plover as an exemplar of a ground-nesting species with precocial young that breeds in grasslands, providing an opportunity to explore site- and breeding stage-specific responses to three categories of environmental covariate thought to drive habitat use in animals: habitat structure, food availability, and predation risk. We monitored nests and broods at two study sites in distinct breeding regions of Colorado and quantified the three covariate categories across standardized site-wide grids in 2021 and 2022. We employed a used vs. available framework in a logistic regression for nest and brood locations and evaluated 10 a priori working hypotheses for which best explains habitat use by the breeding Mountain plover while evaluating the strength of evidence for a dependence on breeding stage. Model selection results suggest that plover use relative to availability is best explained by a nonlinear relationship with vegetation structure which is also dependent on breeding stage. Specifically, probability of use for nests was highest in areas with shorter vegetation, consistent with previous research, while probability of use for broods had a quadratic relationship with groundcover height and bare ground coverage, being highest at the extremes. These results emphasize the importance of investigation of stage-specific habitat use for species with precocial young, particularly species in decline with management strategies that may not consider the full range of habitat requirements.