Demographical and morphological differences among coyotes (Canis latrans) relative to sampling method

Abstract

Collection methods can be biased, leading to misperceptions of population composition. We tested if collection method (footholds, snares, and shooting) gave different perceptions of demography or morphology of 3539 eastern coyotes (Canis latrans Say, 1823). We found no differences in sex ratios of animals among methods, but did find some evidence that younger, lighter, and smaller animals were more likely to be collected by footholds than with snares. Female reproductive histories (placental scars) did not differ among methods. In a subsample of 232 animals, we found no evidence of differences in helminth parasitism relative to collection method. Overall, our large sample for the non-parasite analyses facilitated finding statistical significance; the biological implications hinge on the precision required in estimating population composition and the focal characteristics being compared. For example, mass was 5.3% lower for coyotes caught with footholds versus snares and 10.4% lower for coyotes caught with footholds versus being shot, whereas linear trait measurements of coyotes caught with footholds were generally smaller by at most 4.5% compared with other methods (broadly consistent with linear versus volumetric measurements). Our study provides important baseline information for making inferences about populations of coyotes (and other species) sampled using only a single collection method.