Why Have Gray Fox Numbers Declined?

Although gray fox (Urocyon cinereoargenteus) used to be a common occurrence in much of Illinois, populations have been declining in much of the state since the 1980s. Historically, the state’s gray and red (Vulpes vulpes) fox populations were similar in size, even though distributions statewide were not. Gray fox are “hanging on” in southern and western Illinois where woody habitats are still prevalent and mixed with livestock-grain farms. Trappers in central and northern Illinois used to harvest some gray fox each fall and winter in areas with adequate habitat. More recently, few are taken throughout the state.

Gray foxes are beautiful with their unique combinations of black, pepper-gray, orange-yellow and white fur. They are resourceful, often making do with resources that other wildlife overlook or discard. Orchards with fallen fruit are an attraction as are grape arbors: Grays “steal” Concords and Catawbas fresh off the vine. Grays have a liking for grapes, both tame and wild. Indeed, the native wild grape (Vitis labrusca) of northeastern North America and the tame cultivars developed from this grape are officially called “fox grapes,” a name that is often given to all wild grapes by country folk because they know how foxes love them.

They like woody cover close-by and are out of place in more open landscapes, unlike the red foxes (Vulpes vulpes). Red foxes are at home in open fields but also frequent woodlands—usually by necessity for prey and protection during extreme winter weather. However, grays do hunt smaller farm fields adjacent to the woodlands for favorite prey such as cottontails, mice and voles.

In parts of central and northern Illinois where gray foxes once lived, the patchwork of mixed woodlands and farmlands have been either diminished or completely destroyed. Throughout the state, many woody fencerows and travel corridors, landscape features where grays hunted and moved along, have been eliminated. Certainly, cleaner farming practices have taken their toll.

Although usually secretive and shy, grays may live close to humans, sometimes only a stones-throw away from residential homes in wooded areas, where they have become accustomed to human activities, almost seeming “tame” at times. On occasion, grays den in brush-piles and abandoned groundhog holes in vicinity of woodland homes. On rare occasions, they play with pups in orchards, near gardens and open areas close to houses.

Gray foxes are often described as “catlike” when contrasted to reds. They climb trees and some walls, often going up considerable heights to access summer squirrel nests and bird nests, or to escape predation. Tracks of grays even resembled those of a cat, the outline being more rounded and possibly smaller than a red’s.

Because of dwindling populations, grays are listed on the ‘Watch List’ for Species in Greatest Conservation Need by the Illinois Department of Natural Resources, Wildlife Action Plan. Several possible explanations are being investigated including habitat loss/change, fragmentation, disease and competition with coyotes. The most likely explanation may be a cumulative effect of several of these factors. What is happening to gray fox in Illinois is not unique. Neighboring states including Indiana, Iowa, Missouri and Ohio are also seeing declines.

Possible diseases, such as canine distemper, have been found to affect and kill some gray foxes, but needs additional study to determine how much of an impact this may be having on populations. Canine distemper kills red foxes and coyotes as well. Thus, conclusive evidence that disease is the primary cause of the decline has not been found.

Another possibility is closely correlated with the increases in coyote numbers because coyotes kill both red and gray foxes, almost on sight. Such coyote behavior has been theorized as a reasoned response on the part of a coyote to eliminate one of its main competitors for prey. Others suggest this sort of behavior is instinctive. Regardless of the reasons, coyotes seem to be naturally aggressive towards foxes.

If a fox is intercepted by one coyote in open country, the fox might escape. When two coyotes enter the chase, the outcome is almost certain death for the fox. However, grays live in woody habitats that give them some cover and protection. More escape options are available, and grays are great climbers. Thus, woodland habitats should favor grays escaping from coyotes. Why then have red foxes fared better against coyotes than grays?

One explanation given is that early on when coyote pressure began increasing, red foxes started moving into urban–suburban areas close to humans for protection. Initially, grays didn’t make this “to town” move, although some anecdotal evidence suggests they are now doing so. But why should grays resist such a move? They are shy and secretive; but on occasion, they do live close to humans in woodland settings, a habitat that is home to grays. Perhaps, red foxes accept some urban–suburban landscapes as reasonable facsimiles to the more or less open, natural areas of their liking. On the other hand, maybe grays cannot adjust well to this new environment.

Another possibility is that in some circumstances, gray foxes seem much more aggressive than reds. Grays can be feisty and full of fight. Do they stand their ground against coyotes only to succumb to their much larger and stronger adversaries that may gang up on them?

It is likely that coyote predation/competition at least partly explains why gray fox numbers have declined, but the details are not clear and questions remain. Whatever the reasons, the results are the same. Researchers continue to try and understand what is happening and what managers can do about it. In some areas where this spirited fox was once plentiful, it is now just a mere lingering shadow of its former self.

To learn more about these species visit Wildlife Illinois.

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Robert J. Reber is an emeritus faculty member in the Department of Food Science and Human Nutrition of the University of Illinois at Urbana–Champaign. He has been a lifelong student of many aspects of the Natural World, including archaeology. Bob has served as a managing editor and author for publications such as “The Illinois Steward” magazine and the “Illinois Master Naturalist Curriculum Guide.”