3/9/25: The Tree Fox

Transcript

In 1876, biologist J.A. Allen published a paper entitled “The former range of some New England carnivorous mammals” in which he detailed the historic extent of wolves, lynx, cougars, and several species of carnivorous mammals within the northeast. By the end of the 19th century, many of the animals described had retracted from their pre-colonial ranges. One such animal was the elusive Gray Fox (Urocyon cinereoargenteus). By Allen’s (1876) accounting, this small canine had, at one time, regularly ranged northward through Massachusetts only becoming rare at points further north. In 1876, however, the species had been extirpated north of the Ohio River.

Today, the Gray Fox is a seldom seen, but nonetheless widespread resident throughout New England and, indeed, the southwestern quarter of Maine. Although officially outside of the area reported on many current range maps, I have encountered the species with surprising regularity near my home within the woods of Waldo County, Maine in recent years. My opportunities to observe the species are never very long, ranging from fleeting to momentary. Gray foxes are predominantly crepuscular and nocturnal creatures. Thus, the typical encounter looks like this: is a flash of silver and orange bounding across the roadside at dawn and dusk. Occasionally, however, they will stop to share in a bit of mutual observation with their observer. It is during these 10 to 15 second interactions that the handsome, feline-esque qualities of this animal can be more fully appreciated.

The range expansion of the Gray fox in the Northeast has happened concurrently with the resurgence of the eastern forest. Forests cleared to make way for agriculture in the 18th and 19th centuries have steadily reclaimed the vast areas of abandoned farmland. By the mid-20th century, Gray Foxes had seized upon this period of forest recovery and were documented ranging just beyond our doorstep, occurring throughout Massachusetts, Vermont, and New Hampshire (Palmer, 1954). Since that time, however, the species has taken up residence within the state’s southwestern quarter. Maine is, today, the most forested state within the United States by land area, with nearly 90% of the land cover consisting of forest (USDA, 2020). Although the character of the forestland is variable throughout the state, the secondary forests of Maine’s Southern and Central Interior regions, composed of a mixture of pine, hemlock, along with a variety of hardwood species, have come to offer the Gray Fox suitable habitat for hunting, rearing young, and avoiding predators.

The strong connection between the Gray Fox and the forest can also be seen in the animal’s physiology. Unlike the more familiar Red Foxes, which range throughout the state, Gray Foxes are adept tree climbers. Armed with hooked claws and flexible forearms, this species is capable of scaling tree trunks to evade would-be predators (Allen et al. 2023). This arboreal aptitude has lent the Gray Fox an advantage over the Red in light of the expansion of another canine species within the state: the Eastern Coyote. Coyotes expanded their range northeast in the early 20th century, reaching Maine in the 1930s and filling the void previously occupied by wolves. A recent study examining the relationship between Gray Foxes, Red Foxes, and Eastern Coyotes found that, while Gray Foxes and Eastern Coyotes co-occur within the state, Gray Foxes consume a more varied diet when compared to coyotes and Red Foxes, consisting of more plant matter, with fruits being an important component of their diets (Masters et al. 2022). Additionally, elsewhere within their shared ranges, Gray Foxes have been found avoiding competition with (and potential predation by) coyotes by hunting and foraging primarily at night while coyotes favor the daylight hours (Rodríguez-Luna et al. 2024).

The period of northeastern Gray Fox expansion is ongoing, with sub-adults pushing beyond the limits of their known ranges seeking to establish new territories (Environment and Climate Change Canada, 2017). Observations of the species within the Penobscot River valley are increasing and, in 2023, an individual was captured on a game camera in the lowlands just northeast of Katahdin (Smith, 2023). Although any instance of breeding has yet to be documented, the species was also recently observed in New Brunswick (Environment and Climate Change Canada, 2017).

The continued range expansion of Gray Fox in the northeast serves as both a testament to the species’ resilience to anthropogenic change over the centuries and a reminder of the complex interactions that exist between individual species and a dynamic landscape. Given their relatively recent occurrence within the region, much remains for us to learn about how Gray Foxes contribute to the biodiversity of New England’s ecosystems.

Citations:

Allen, J. A. (1876). The former range of some New England carnivorous mammals. The American Naturalist, 10 (12), 708-715.

Allen, M. L., & Kritzer, J. P. (2023). Observations of Gray Fox Urocyon cinereoargenteus (Schreber, 1775) (Mammalia: Carnivora: Canidae) denning behavior in New Hampshire, USA. Journal of Threatened Taxa, 15 (8), 23662-23668.

Environment and Climate Change Canada. 2017. Recovery Strategy for the Grey Fox (Urocyon cinereoargenteus) in Canada [Proposed]. Species at Risk Act Recovery Strategy Series. Environment and Climate Change Canada, Ottawa. ix + 42 pp.

Masters, H. M., & Maher, C. R. (2022). Diet reveals potential for competition and coexistence among coyotes (Canis latrans), red foxes (Vulpes vulpes), and gray foxes (Urocyon cinereoargenteus). Canadian Journal of Zoology, 100(2), 90-97.

Palmer, R. S. (1954). The Mammal Guide: mammals of North America north of Mexico. Doubleday & Company, Inc.

Rodríguez-Luna, C. R., Servín, J., Valenzuela-Galván, D., & List, R. (2024). A matter of time not of co-occurrence: temporal partitioning facilitates coexistence between coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) in temperate forests of Mexico. Mammalian Biology, 104(4), 363-377.

Smith, K. 2023. iNaturalist observation: https://www.inaturalist.org/observations/158050762. Accessed on 12/14/2024.

USDA Forest Service. (2020). Forests of Maine, 2019. Resource Update  FS-236. Madison, WI: U.S. Department of Agriculture, Forest Service. 2p.  https://doi.org/10.2737/FS-RU-236 .