Vital Statistics and Harvest of an Iowa Raccoon Population

• Published in: The Journal of wildlife management 1989-10, Vol.53 (4), p.982-990
• Main Authors: Clark, William R., Hasbrouck, James J., Kienzler, James M., Glueck, Thomas F.
• Format: Article
• Language: English
• Subjects: Age; Age structure; Agricultural seasons; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Demecology; Female animals; Fundamental and applied biological sciences. Psychology; Harvesting seasons; Litter size; Mammalia; Mortality; Pregnancy rate; Procyon lotor; Vertebrata; Vital statistics; Wildlife; Yearlings
• ISSN: 0022-541X; 1937-2817
• DOI: 10.2307/3809599

We studied reproduction, survival, and dispersal of an exploited raccoon (Procyon lotor) population in Iowa farmlands during 1982-86. Mean pregnancy rate of yearlings was 59%, significantly less than the 91% observed among animals ≥2 years old. Pregnancy rate was best predicted by a logistic regression function of age, carcass weight, and their interaction. Litter size of 3.1 young/yearling female, was significantly less than the 3.8 young/adult female. We found no differences in survival of yearlings and older raccoons or between males and females. A single rate adequately represented survival of all raccoons during the nonharvest seasons (Jan-Oct). Juvenile survival, from age 4 months through the end of the harvest season, ranged from 0.37 to 0.78. Annual survival of adults ranged from 0.47 to 0.75. Harvest and vehicle accidents accounted for 78 and 10% of all recoveries, respectively. Juvenile and adult survival were not significantly different during any of the harvest seasons. Eighty nine percent of the harvest occurred in the first month of the open season. We estimated maximum potential harvest to be 41% of the preharvest population; observed harvest was 32%. There is potential for density-dependent compensation among mortality sources during the harvest season, in mortality among young and adults in following seasons, and in reproduction.