The n-player war of attrition and territorial groups

The choices made by juveniles, in territorial species, between dispersing and remaining in the natal territory, can be modelled as a simple multi-player evolutionary game, related to the well-known War of Attrition [Maynard Smith, J. (1974) J. theor. Biol. 47, 209-221; Haigh J. & Cannings, C. (1989) Acta Applicandae Mathematicae 14, 59-74]. The game is shown to have a unique evolutionarily stable strategy, involving a random choice between dispersing early in the game and staying indefinitely. An example is given, involving badgers (Meles meles), in which the key factor affecting the pay-off in the game is the possibility of inheriting the territory on the death of the current holders. The example indicates the sensitivity of the size of the group occupying the territory to the mortality rate among dispersers.