Northern Prairie Wildlife Research Center
Previous studies have investigated the diet of wild populations of swift fox (Uresk & Sharps 1986, Great Basin Nat. 46:249-253; Zumbaugh et al. 1985, Prairie Nat.17:41-47; Hines & Case 1991, Prairie Nat. 23:131-138), and two studies have examined the diet of captive swift fox in large group enclosures (Carlington 1980, MS thesis Univ. of Calgary, Calgary, AB; Stephens & Etemadi 1994, Unpubl. Rept. Cochrane Ecol. Inst.), however, there have been no investigations into the diet of captive breeding pairs maintained in single-pair enclosures.
Scats from 20 single-pair enclosures were examined to determine whether swift fox were supplementing their diet through hunting and if the level of hunting behaviour could be increased through the introduction environmental enrichment. Ten enclosures had environmental enrichment introduced in the form of wood-piles, and regular scattering of bird-seed, whilst the remaining ten enclosures were maintained as controls. Fifteen hundred seventy one scats were collected and analyzed, based on modifications to a technique developed Uresk & Sharps (1986). Food items in scats were recorded according to frequency of occurrence.
Results show the presence of hunting behaviour in both the control and enriched pens with distribution of food items displaying similar patterns. Frequencies of occurrence were significantly higher for microtines in the experimental enclosures.
The primary content of scats indicates a higher level of hunting of small rodents in the enriched pens than in the control pens. Vegetation occurred frequently, with few scats containing less than one type of vegetation.
The presence of hunting behaviour within the single-pair enclosures has important implications for those foxes destined for reintroduction, and for the welfare of those retained as part of the breeding colony. Every effort should be made to encourage and increase the levels of hunting behaviour already present.