Responses of Red Squirrel (Tamiasciurus hudsonicus) Populations to Supplemental Food

Abstract

In this study I determined the responses of red squirrel (Tamiasciurus hudsonicus) populations to long-term supplemental food and tested the hypothesis that squirrel populations are limited by available food. Squirrel populations were sampled by live trapping on replicate study areas in mature coniferous forest near Prince George and in the Cariboo, British Columbia from June 1983 to June 1986. The average abundance of squirrels in fed populations was 3–4 times higher than in controls during the 2 years of supplemental feeding. More adults were recruited into fed than into control populations. The fed population had longer breeding seasons and some females may have had two litters compared with only one in the controls. There were no consistent differences in survival between control and fed populations. Population densities declined slowly after the food was withdrawn from the experimental areas, and population characteristics gradually approached those of the control. Food limits population size in the red squirrel and is likely a driving factor in population fluctuations.