Wesołowski T. 1981. Population restoration after removal of wrens (Troglodytes troglodytes) breeding in primaeval forest. Journal of Animal Ecology 50: 809-814.

(1) This study was done in the last fragments of primaeval temperate European forest preserved in Białowieża National Park in N.E. Poland. (2) Wrens occur here in low densities, up to five territories 10 ha-1 in optimal habitats and below two territories 10 ha-1 in suboptimal ones. The hypothesis of proximate limitation of numbers by territorial behaviour has been tested. (3) Removal experiments were carried out in suboptimal habitats, after the end of the spring migration. (4) Removal of territorial males on two occasions did not cause any signficant change in number of territories within the plot. (5) The plot was repopulated mainly by previously non-territorial males. The replacement birds were physiologically capable of reproduction. (6) It is suggested that a non-breeding element of population exists in most years. (7) The role of territorial behaviour as a factor limiting numbers of wrens in primaeval forest is confirmed.