# Multiscale Nest-Site Selection of Burrowing Owl (Athene cunicularia) in Chihuahuan Desert Grasslands

## TL;DR

Burrowing owls in northern Mexico choose nesting sites based on a combination of burrow, colony, and landscape features, emphasizing the need to protect prairie dog colonies and reduce human disturbance.

## Contribution

The study introduces a multiscale analytical framework to evaluate how Burrowing owls select nesting sites in relation to Mexican prairie dog colonies and surrounding landscapes.

## Key findings

- Owls prefer burrows with greater internal space and protection, near other burrows in colonies with moderate prairie dog activity.
- Nest-site selection is influenced by reduced predation risk and agricultural disturbance at the landscape scale.
- A multiscale model outperformed single-scale models, showing that nesting decisions emerge from interactions across spatial scales.

## Abstract

Burrowing owls depend on underground burrows to reproduce, but these burrows are not consistently available across landscapes. In northern Mexico, Burrowing owls rely almost entirely on burrows created by Mexican prairie dogs, an endemic species currently at risk of extinction due to habitat loss. Understanding how owls choose where to nest is essential for protecting both species and the grasslands they inhabit. We examined how Burrowing owls select nesting sites across spatial scales, from the characteristics of individual burrows to broader landscape features. We found that owls prefer burrows that offer greater internal space and protection, are located near other available burrows, occur in prairie dog colonies with moderate activity, and are found in landscapes with fewer structures that predators can use and farther from croplands. Our results show that nesting decisions are shaped by a combination of local and landscape conditions rather than by a single factor. These findings highlight the importance of conserving functional prairie dog colonies and maintaining low levels of human disturbance in grassland ecosystems. Protecting these conditions will help ensure suitable breeding habitat for Burrowing owls and support the conservation of grassland biodiversity in northern Mexico.

Nest-site selection in birds is a hierarchical process shaped by environmental filters operating across multiple spatial scales. In species that depend on burrows excavated by ecosystem engineers, understanding how these filters interact is essential for effective conservation. We evaluated nest-site selection by the Burrowing owl (Athene cunicularia) within colonies of the Mexican prairie dog (Cynomys mexicanus) in the southern Chihuahuan Desert using a multiscale analytical framework spanning burrow, site, colony, and landscape levels. During the 2010 and 2011 breeding seasons, we located 56 successful nests and paired each with an inactive non-nest burrow within the same colony. Eighteen structural and environmental variables were measured and analyzed using binary logistic regression models, with model selection based on an information-theoretic approach (AICc) and prior screening for predictor collinearity. Nest-site selection was associated with greater internal burrow development and reduced external exposure at the burrow scale, proximity to satellite burrows and low-to-moderate vegetation structure at the site scale, higher densities of active prairie dog burrows at the colony scale, and reduced predation risk and agricultural disturbance at the landscape scale. The integrated multiscale model showed substantially greater support and discriminatory power than single-scale models, indicating that nest-site selection emerges from interactions among spatial scales rather than from isolated factors. These findings support hierarchical habitat-selection theory and underscore the importance of conserving functional Mexican prairie dog colonies and low-disturbance grassland landscapes to maintain suitable breeding habitats for Burrowing owls in the southern Chihuahuan Desert.