Why are coyote populations difficult to control?

Conventional wisdom suggests that coyote control efforts actually result in an increase in the number of coyotes due to increasing litter sizes and pregnancy rates among individuals that survive. New research published in the Journal of Wildlife Management demonstrates that while litter size and pregnancy rates tend to increase somewhat after heavy trapping pressure, overall reproductive capacity of the population declines.

The reduced reproductive capacity is due to an increased representation of juveniles in the population, which rarely breed, coupled with a concurrent decrease in adults, which account for most of the breeding. A high influx of immigrants, many of which are younger animals vying for territories, render coyote populations extremely difficult to control, however.

"This work sheds a little more light on how coyote populations are able to recover so quickly from heavy persecution—increased immigration seems to be much more important than increased reproduction," said Dr. John Kilgo, lead author of the study.