MATE GUARDING IN THE CHIFFCHAFF PHYLLOSCOPUS-COLLYBITA

In bird species, several behavioural strategies have evolved to facili tate the avoidance of cuckoldry, such as mate guarding, frequent copul ation, territory defence, and song signals. The present study describe s mate guarding in the chiffchaff, Phylloscopus collybita, and reports an experimental manipulation aimed at discovering whether females eng age in extra-pair copulations in the absence of their males. The data indicate that the males were responsible for maintaining and increasin g pair proximity during the period just before the females start layin g their eggs. Also, most successful pair copulations took place in the days immediately before egg laying. These findings are consistent wit h the predictions of the sperm competition hypothesis, i.e. the male a chieves mate guarding by maintaining close proximity and following the female during her fertile period constitute mate guarding. However, t he female-advantage hypothesis cannot be refuted because the female co uld be inducing male proximity through contact calls. Also, during the experimental removal of the male from the territory, females did not leave the territory and were unwilling to accept extra-pair copulation s (EPC). This immediate female rejection may be evidence that there is a cost to the female in engaging in an EPC. It is suggested that mate guarding could have other functions besides paternity assurance.