Abstract: A conflict for a nesting site between two dendrophilous ant species, Camponotus vagus (Scopoli, 1763) and C. herculeanus (Linnaeus, 1758) in the Białowieża Forest (Poland) is described. A colony of the former unsuccessfully tried to take over a log dwelled by a colony of the latter and its plesiobiotic partner, a colony of Formica fusca Linnaeus, 1758. A competitive basis and a course of the conflict are discussed.