The fitness and survival of ant colonies depend on the resources near their nests. These resources may be limited due to poor habitat quality or by intra- and interspecific competitions, which in extreme cases may cause the ant colony to perish. We tested the effect of intraspecific competition and habitat degradation (forest clear-cutting) on colony survival by transplanting 26 nests of the red wood ant (Formica aquilonia Yarrow, 1955) in 26 different forest areas that contained 0-11 conspecific alien nests per hectare. E aquilonia is highly dependent on canopy-dwelling aphids, thus the removal of trees should cause food limitation. During the course of the 4-year experiment, 9 of the forests were partially clear-cut. We found that while forest clear-cutting significantly decreased the colonies' survival, intraspecific competition did not. As a highly polygynous and polydomous species, E aquilonia seems to tolerate the presence of alien conspecific colonies to a certain extent.