Settlement behaviour and population dynamics of reintroduced red squirrels Sciurus vulgaris in a park in Antwerp, Belgium Original Research Article

The demography of red squirrels Sciurus vulgaris removed from three different source areas and reintroduced between February 1987 and January 1988 in an urban park near Antwerp, Belgium was monitored for six years. Animals that were used to human presence had a higher initial survival than those not accustomed to human disturbance. Contrary to our predictions, woodland structure at the removal site did not affect a squirrelʹs settlement success, and post-release survival of subadults was not higher than that of adults. Only three (33%) introduced males, and five (50%) females survived to produce offspring. Reproductive rate was density-dependent and tended to increase with food abundance (tree seed crop of beech and oak). Consequently, population growth was high the first three years (low density) and decreased after 1990 (high density), when both adult and post-breeding densities (0·8–0·9 squirrels/ha) remained stable, suggesting the reintroduced population had reached its equilibrium density. We discuss some guidelines to increase the success of red squirrel reintroduction projects.