Abstract
Two encounters between brood-attending grouse hens (Tetraonidae) and a red fox Vulpes vulpes are described. In both the fox ignored the hen''s distraction display. Moreover, at least in the second encounter, the hen''s display immediately triggered searching behaviour in the fox. Based on these observations a simple game theory model was constructed to predict when distraction displays will be more profitable than just flying off. Assuming that foxes either always start searching for chicks when the hen performs display ("smart " foxes) or always are lured away ("dumb" foxes), and that old foxes are more often "smart" than young ones, the model predicts how the frequency of display towards foxes in brood-attending hens should vary during a microtine rodent cycle in boreal Fennoscandia. The predicted variation matches observed annual variation in distraction displays towards humans with pointing dogs by brood-attending willow ptarmigan hens Lagopus lagopus.