MALE TERRITORIALITY AND FEMALE CHOICE ON BLACK GROUSE LEKS

Two, not mutually exclusive, hypotheses for how female choice of males could explain male territory settlement patterns on leks have recently been proposed. First, the 'temporal spillover hypothesis assumes that females return to previously popular mating sites. If the previous owner of such a popular site disappears it will pay other males to defend such areas of the lek. Second, the spatial spillover hypothesis assumes that unsuccessful males gather around the most successful males to achieve copulations from females with which top males for some reason fail to mate. In the black grouse, Tetrao tetrix, there were no indications of temporal spillover between successive years. While individual males retained their popularity to some degree, there was no consistency in the popularity df the same locations per se. Instead, some spatial spillover is suggested by the fact that new territories in each season were established closer to the copulation centre than to the lek centre of the previous year. Furthermore, males close to the preferred males seemed to achieve copulations because of their proximity to such males. Successful males did not change their territorial position, but less preferred males tended to move closer to the lek centre filling the vacancies arising from any yearly mortality of males. While spatial spillover explains only a minor proportion of matings, most females choosing males independent of their site, it may be the only chance for poor quality males to obtain matings.