Effect of Predator Control on Coyote Age Structure, Weight, and Reproduction

Abstract

Predator control on coyotes (Canis latrans) has been extensive throughout the western United States. A common biological expectation is that reproduction increases as density of coyotes is reduced. However, this expectation does not consider social structure, age structure, or prey availability before and after predator control is undertaken. We examined the effects of predator control on coyote age structure, weight, and reproduction in three study units in north-central Montana. Study units ranged from 140 to 2679 km2 and were subjected to different levels of control intensity. Coyote age structure did not change significantly over time within individual units. Among treatment areas, only the area most intensively controlled differed significantly in age structure, having younger coyotes. Based on corpora luteal counts, coyote reproduction increased only within the largest unit, which was subjected to intense control. Coyotes were younger, larger, and more reproductively active when subjected to intensive control over a large area. Significant differences in age or reproduction were not apparent for units of smaller size or less intensive control efforts.