Estimates of Some Attributes of a Population of Nuttall's Cottontails

• Published in: The Journal of wildlife management 1978-01, Vol.42 (1), p.159-168
• Main Authors: McKay, Donald O., Verts, B. J.
• Format: Article
• Language: English
• Subjects: Breeding; Breeding seasons; Density estimation; Estimation methods; Mortality; Population density; Population estimates; Rabbits; Reproduction; Young animals
• ISSN: 0022-541X; 1937-2817
• DOI: 10.2307/3800704

Density, natality, and mortality of a population of Nuttall's cottontails (Sylvilagus nuttallii) in shrub-juniper scabland of central Oregon were monitored from August 1972 to March 1974. Monthly censuses indicated population density ranged from 6.6 to 254.4/100 ha. Densities declined 89 and 85 percent from August to December in 1972 and 1973, respectively; within these periods, greatest losses occurred at times of unusually low minimum daily temperatures. In 1972, 4 litters were produced (April-July) of which 10, 22, 68, and 80 percent, respectively, survived to 30 August. In 1973, only 3 litters were produced (April-June) of which 25, 21, and 11 percent survived to 30 August. The decline in production and survival of juvenile cottontails in summer 1973 was believed to be related to reduced precipitation during the reproductive period; precipitation was 64 percent less in 1973 than in 1972. Differential survival of litter groups indicated that drought had the greatest impact on younger cohorts, perhaps through reduction in succulent forage for weanlings.