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Providing evidence to improve practice

Individual study: Responses of red squirrel (Tamiasciurus hudsonicus) populations to supplemental food

Published source details

Sullivan T.P. (1990) Responses of red squirrel (Tamiasciurus hudsonicus) populations to supplemental food. Journal of Mammalogy, 71, 579-590


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Provide supplementary food to increase reproduction/survival Terrestrial Mammal Conservation

A replicated, paired sites, controlled, before-and-after study in 1983–1986 in four mixed spruce and pine forest sites in British Columbia, Canada (Sullivan 1990) found that providing supplementary food increased the abundance of red squirrels Tamiasciurus hudsonicus. After two years, squirrel abundance in sites with supplementary food was higher (41–53 squirrels/site) than in unfed sites (9–15 squirrels/site). One year after supplementary feeding ceased, squirrel numbers declined in previously fed sites (23–31 squirrels/site) but not in unfed sites (11–12 squirrels/site). A 9-ha grid, with 100 stations at 30 m intervals, was established in each of four forest sites (two each in two forests). Sunflower seeds (83–90 kg/month) were provided in cans nailed to trees distributed across two sites (50 cans/site), from September 1983 to September 1985. No food was provided at the other two sites. From June 1983 to June 1986, squirrels were captured and measured using one Tomahawk live trap at alternate stations. Traps were set for two days, every 3–4 weeks in summer (April–September) and 4–10 weeks in winter (October–March). Cans were refilled after each trapping period.

(Summarised by Ricardo Rocha)