Reproductive characteristics of a coyote population before and during exploitation

The eastward expansion of coyotes (Canis latrans) has brought the species into ecosystems and landscapes different from those it historically occupied, yet little is known about the reproductive biology of coyotes in the southeastern United States or the effects of exploitation on reproduction in coyotes. Our objective was to quantify litter size, pregnancy rate, and fecundity in an essentially unexploited coyote population in South Carolina, USA and to evaluate the effect of exploitation on these parameters. We examined reproductive tracts from 235 female coyotes trapped during 2010–2012. Placental scars from coyotes trapped during 2010 indicated that prior to trapping (2009), pregnancy rates were zero for juveniles, 0.25 for yearlings, and 0.389 for adults. Litter size for adults during 2009 averaged 5.4 pups/female, resulting in fecundity of 2.1 pups/female. The number of coyotes trapped was similar among years, indicating that the population recovered following trapping each year, but it shifted toward a younger age structure during trapping. However, although pregnancy rate, litter size, and fecundity of adults all tended to increase from pre-trapping (2009) through the last trapping period (2011–2012), differences were not significant for this or any other age class. Fecundity of the population did not significantly increase during the first year of trapping (2010) but was lower during the last trapping period (2011–2012; 0.56 ± 0.15 [95% CL]) than prior to trapping (0.90 ± 0.15 [95% CL]). Thus, we observed only weak evidence for compensatory reproduction in response to trapping pressure and conclude that the increase in the juvenile component of the population was attributable primarily to immigration from neighboring areas rather than in situ reproduction. This increased representation of juveniles in the population, which rarely bred, coupled with a concurrent decrease in adults, which accounted for 59.2% of breeding, explains the reduction in population fecundity. High immigration rates as indicated herein render coyote populations extremely difficult to control. © 2017 The Wildlife Society.