Seasonal food habits of corsac and red foxes in Mongolia and the potential for competition

Abstract

Competition often occurs between sympatric species that exploit similar ecological niches. Among canids, competition may be reduced by partitioning resources such as food, time, and habitat, but the mechanisms of coexistence remain poorly understood, particularly among fox species. We described the food habits of two foxes that live sympatrically across northern and central Asia, the corsac fox (Vulpes corsac) and red fox (V. vulpes), by analyzing scats collected during a field study in Mongolia. We analyzed 829 corsac and 995 red fox scats collected from April 2005 to August 2007 and tested the extent to which food partitioning occurred. The diets of both species consisted mainly of insects followed by rodents, but also included birds, reptiles, large mammal remains (carrion), plant material (including fruits and seeds), and garbage. Despite high overlap in the proportion of food items consumed, differences existed between species in overall diet with corsacs more frequently consuming beetles, but proportionally fewer crickets and large mammal remains than red foxes. We detected interspecific differences during the pup rearing and dispersal seasons, when prey was abundant, but not during the breeding season, when prey was scarce and diet overlap highest. Each species' diet also differed seasonally and exhibited moderate overall breadth. Corsacs consumed proportionally more beetles and rodents during pup rearing and crickets during dispersal relative to other seasons, whereas red foxes consumed proportionally more crickets during pup rearing and dispersal and more rodents and large mammals during pup rearing and breeding relative to other seasons. Our results suggest that partitioning of food resources during most of the year facilitates coexistence, and that the potential for competition is highest during winter months.

An account of badger diet in an arid steppe region of Mongolia

“…Insects were highly abundant in Ikh Nart during summer and autumn (Murdoch et al, 2010), perhaps explaining their frequent occurrence in scats. Orthoptera, in particular, composed most scats and exhibited large peaks in abundance during the study.…”

Siberian Ibex (Capra sibirica) Neonatal Kid Survival and Morphometric Measurements in Ikh Nart Nature Reserve, Mongolia

“…A study of red fox diet found an increase in ungulate hair occurrence in April to May, when both foxes and ibex give birth and rear their young (Buyandelger, 2008;Murdoch et al, 2010). Other studies found lower annual survival rate (> 37.5%) in the face of fox and wolf predation in the Tian Shan Mountains (Egorov, 1955).…”

When prey provide more than food: mammalian predators appropriating the refugia of their prey

“…The exceptions are the small foxes that regularly use burrows for shelter, including, for example, the swift fox (Vulpes velox), kit fox (Vulpes macrotis), and corsac fox (V. corsac). The latter uses the burrows of the Siberian marmot (M. sibirica) but does not prey on this relatively large herbivore (Murdoch et al 2010). …”

“…I exclude these circumstances from consideration. For example, the Pallas's cat (Otocolobus manul) and corsac fox (Vulpes corsac) use the burrow system of the Siberian marmot (Marmota sibirica) for resting, but do not prey on this species (Murdoch et al 2010;Ross et al 2010a, b). Similarly, non-trophic relationships occur between the red fox (Vulpes vulpes) and woodchucks (Marmota monax) and between meerkats (Suricata suricatta) and Cape ground squirrels (Xerus inauris) (Stanley 1963;van Staaden 1994).…”