Factors affecting male mating success in red squirrels (<i>Sciurus vulgaris</i>)

The mating behaviour and the factors affecting male mating success in individually marked free-ranging red squirrels (Sciurus vulgaris) were studied over a 4 year period with the aid of radio-telemetry. In the coniferous area 12 mating-chases were observed against 14 in the deciduous study area. A mean of 3.19 adult males took part in a mating-chase, one of which was the leading male that defended the oestrous female. The leading male accounted for 24 of the 29 observed matings, while in five cases other males were able to mate successfully. The leading male had in general the highest dominance rank, and the highest body weight of all competitors. It was normally an older male with large testes. The position of the leading male in a chase was stable in time and in space, although on two occasions it abandoned the female when she moved outside its home range. The relative success of three different mating strategies: the protective leader strategy, the persistent male strategy, and the sneaker male strategy, is discussed.