POLYGYNY AND DECEPTION IN THE PIED FLYCATCHER - CAN FEMALES DETERMINEMALE MATING STATUS

The polyterritorial pied flycatcher, Ficedula hypoleuca, was used to i nvestigate the deception hypothesis, which states that mated males beh ave as unmated to hide their mating status from prospecting females. P revious studies on this species have shown that unmated and mated male s differ in territorial presence, but not when females are present in their territories. Male behaviour after female visits may differ, howe ver, and this was tested in the present study. Caged females were pres ented to males during periods of 5 min and the behaviour of the males in the following hour was recorded. Mated males were present significa ntly less often in their territories than unmated males. Video-recordi ngs of male behaviour after natural female visits indicated that mated males spent less time singing than unmated males, suggesting that the y were often absent from their territories. Given this difference, fem ales can potentially determine male mating status by making repeated r eturns to the territories of males they have visited, and sampling the presence of the males. Field data showed that females visited their c hosen mate 5-37 times before mating. A model is presented which gives the probability of rejecting mated males, depending (1) on the number of repeated visits and (2) on how many of these visits a male should b e present to be classified as unmated. The model also describes one co st of such behaviour, namely that of rejecting unmated males. The mode l indicates that females can reject up to 87-99% of the mated males by visiting males 5-37 times. In conclusion, male deception of females m ay be countered by females using the repeated visits strategy.