Northern Prairie Wildlife Research Center
Why have fox and coyote distribution changed so much over such a large area? We suspect several reasons.
Many relative distribution changes were created by government policy, mainly at the federal level. For example, in 1972 there was a federal ban (by Presidential executive order) on the use of toxicants for predator control, and the federal airplane hunting act was also signed into law.
Both changes had an impact on red fox and coyote populations in North Dakota. Mortality pressure on both species declined, but was most pronounced for coyotes. The response was better coyote and red fox survival rates in the short run. In the long run, coyote survival rates continued to improve, resulting in greater distribution relative to red fox. Red fox survival rates and distribution began to decline because of increasing coyote numbers.
The Missouri Slope and Missouri Coteau graphs show this best. Coyote densities probably have not increased in the Drift Prairie and Red River Valley to the point where they would dramatically impact the relative distribution of red fox.
Can management changes alter this trend - in either direction? The primary answer rests in the nature and direction of federal predator control policy.
The main opposing forces that determine coyote and fox numbers annually are reproduction and mortality. Policy changes mainly influence mortality. The greatest changes in fox or coyote population will likely occur if there is a change in policy toward coyotes.
A change in favor or against coyotes will obviously impact coyote distribution. Changes in coyote distribution will ultimately affect red fox distributions as well.
On the other hand, a change in policy toward red fox will only affect fox distribution. Further, such a change may not have much real impact, because coyote influence on red fox may override any policy changes toward foxes. We suspect that the greater the change in coyote mortality rates, the greater the change in relative distribution of both species.