Reproductive characteristics and performance of the Florida panther: a retrospective examination of long-term data

Knowledge of reproductive characteristics and performance (RCP) is necessary to estimate a species’ breeding output and provide indicators to evaluate population health and sustainability. Long-term data is important because it provides insights into the role of intrinsic and extrinsic factors in determining RCP and lifetime breeding output of individuals and productivity of populations. In this paper, I examine the RCP of the Florida panther Puma concolor coryi using an extensive data set collected from 1981-2019. My objective is to establish baseline RCP parameters and to determine the factors that affect lifetime breeding output. Briefly, the results from a variety of data analyses show: 1) Florida panthers exhibit a spring (March-May) birth pulse; 2) minimum age at sexual maturity do not differ between sexes; 3) mean annual proportion of radio-collared females reproducing, litter size, and birth rate progressively decrease with increasing maternal age; 4) mean litter sex ratio is male-biased; 5) mean birth interval differs between successful and unsuccessful litters; 6) proportion of kittens that recruited into the breeding population is small; and, 7) distribution of parentage and mating partners among individuals in litters of known mothers and fathers is right-skewed. The results indicate that breeding output is limited both by low birth rate and small proportion of offspring recruiting into the breeding population. The decreasing RCP with increasing maternal age suggests that costs of reproduction and progressive body condition senescence are important factors limiting lifetime breeding output. Despite these inhibiting factors, the data came from a period of substantial population growth and expansion since 1995 so the RCP shown is productive for this species. Outcomes from this study provide important RCP information for wildlife managers to implement measurable criteria to assess trends in this species’ breeding output.