Space use and territoriality in swift foxes (Vulpes velox) in northeastern Colorado

Space use is a fundamental characteristic that informs our knowledge of social relationships and the degree to which individuals are territorial. Until recently, relatively little was known about the spatial ecology and social organization of swift foxes (Vulpes velox (Say, 1823)). We investigated space use of swift foxes on shortgrass prairie in northeastern Colorado. Our first objective was to evaluate sizes of seasonal and annual home ranges and core areas of 13 radio-collared swift foxes monitored continuously for 2 years. Our second objective was to compare home-range and core-area overlap of breeding pairs to that of neighboring foxes, including male-male, female-female, and nonbreeding female-male dyads. Home-range size in our study population was among the smallest previously reported for swift foxes. Males tended to have slightly larger home ranges and core areas than females, and home-range size was significantly larger in the breeding season than in both the pup-rearing and the dispersal seasons; sizes of core areas did not differ seasonally. Spatial overlap between breeding pairs was substantial, whereas spatial overlap between neighbors, particularly males, was low, suggesting territoriality. Key words: Vulpes velox, home range, core area, seasonal, overlap, territoriality. L'utilisation de l'espace est une caracteristique fondamentale qui permet de connaitre les relations sociales et l'importance de la territorialite chez les individus. Jusqu'a recemment, on savait relativement peu de choses sur l'ecologie spatiale et l'organisation sociale des renards veloces (Vulpes velox (Say, 1823)). Nous avons etudie l'utilisation de l'espace chez les renards veloces dans la prairie d'herbes courtes du nord-est du Colorado. Notre premier objectif etait d'evaluer les domaines vitaux saisonniers et annuels et les aires centrales de 13 renards veloces porteurs de colliers radio suivis continuellement pendant 2 annees. Notre second objectif etait de comparer le chevauchement des domaines vitaux et des aires centrales des couples reproducteurs a celui de renards voisins, incluant des dyades male-male, femelle-femelle et femelle-male non reproducteurs. La taille du domaine vital observe dans la population etudiee est parmi les plus petites jamais signalees chez le renard veloce. Les males ont tendance a posseder un domaine vital et une aire centrale plus etendus que ceux des femelles; la taille du domaine vital est significativement plus grande durant la saison de reproduction que durant les deux saisons d' elevage des petits et de dispersion. La taille des aires centrales ne varie pas en fonction de la saison. Le chevauchement spatial est considerable entre les couples reproducteurs, alors que le chevauchement spatial entre les voisins, particulierement les males, est faible, ce qui laisse croire a l'existence de territorialite. Mots-cles : Vulpes velox, domaine vital, aire centrale, saisons, chevauchement, territorialite. [Traduit par la Redaction]
Introduction Space use is a fundamental behavioral and ecological characteristic that informs our knowledge of an animal's interactions with its environment, including relationships with others in the population and the [...]