Temporal Avoidance by Gray Foxes Reflects Growing Pressure from Expanding Coyotes in the Neotropics

Author

• Madison OdenbachFollow

Graduation Year

2026

Graduation Month

May

Document Type

Thesis

Degree Name

Bachelor of Science

School or Department

Wildlife Biology

Major

Wildlife Biology – Terrestrial

Faculty Mentor Department

Wildlife Biology

Faculty Mentor

Mark Hebblewhite

Faculty Reader(s)

Erím Gómez, Victoria Dreitz

Keywords

temporal overlap, Costa Rica, competition, partitioning, niche, co-occurrence

Subject Categories

Behavior and Ethology | Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology | Zoology

Abstract

Coyotes (Canis latrans) are rapidly expanding their range towards South America, potentially threatening the world’s highest canid diversity residing on that continent. A better understanding of their interactions with native species is needed to anticipate potential competitive impacts. In Costa Rica, native gray foxes (Urocyon cinereoargenteus) likely occupy a similar niche to the coyote newcomer, yet little data exists on their interactions in tropical ecosystems. We hypothesized the two species separate temporally to minimize the potential for competition in our study area, given preliminary data suggesting high spatial overlap (57.1% of coyote-detected sites overlap with fox-detected sites; 80.0% of fox sites overlap with coyote-detected sites). Camera-trap analysis revealed moderate temporal overlap (Δ₄ = 0.56). Detection frequencies varied significantly across diel periods (Chi-square: p < 0.001); foxes were primarily nocturnal, while coyotes were more diurnal and crepuscular than expected. Permutation analysis (10,000 iterations) revealed significant temporal separation in site use across three temporal scales reflecting scent persistence: untruncated (i.e., across the entire study period, 14-day, and 7-day). At the untruncated scale, observed medians for time-to-encounter were longer than chance for coyote-then-fox (observed: 27.4 days; expected: 16.8 days) and fox-then-coyote (observed: 26.0 days; expected: 12.0 days), though given the large delays at this scale, results may reflect factors beyond avoidance. The effect was strongest at the 7-day scale for coyote-then-fox (observed: 3.78 days; expected: 1.38 days) and fox-then-coyote (observed: 3.15 days; expected: 1.08 days), suggesting mutual avoidance of recently visited sites. While activity patterns moderately overlap, the two species may reduce the potential for competition through mutual temporal avoidance through diel habitat partitioning. Behavioral adjustments imposed on gray foxes that our work suggests may represent a stress cost that foreshadows disruption to native canid communities as coyotes advance toward South America.

Honors College Research Project

1

GLI Capstone Project

no

Recommended Citation

Odenbach, Madison, "Temporal Avoidance by Gray Foxes Reflects Growing Pressure from Expanding Coyotes in the Neotropics" (2026). Undergraduate Theses, Professional Papers, and Capstone Artifacts. 591.
https://scholarworks.umt.edu/utpp/591