FEMALE EUROPEAN STARLINGS INCREASE THEIR COPULATION SOLICITATION RATEWHEN FACED WITH THE RISK OF POLYGYNY

Since primary females in most polygynous birds receive less male help in feeding nestlings than monogamous females, paired females should tr y to prevent or delay the settlement of other females. Recently, it ha s been suggested that a female may copulate repeatedly with her mate t o reduce the likelihood that he mates with other females. One of the p redictions of this female mate-guarding hypothesis is that females sho uld solicit at times when there is a risk that their male partners wil l mate with other females. To test this prediction, the response of ca ptive female European starlings, Sturnus vulgaris, that had an exclusi ve male partner to their male courting a newly introduced female was e xamined. Resident females significantly increased their copulation sol icitation rate after their male started courting the new female. Most of the resident females' copulation solicitations occurred close to th e nestbox where their male was trying to attract the newly introduced female, which may suggest that females use the solicitation of copulat ions to distract their male from the prospecting female. Resident fema les also behaved aggressively towards the newly introduced females. Ma le starlings played an active role in moderating female conflicts: the y interrupted about 60% of the resident females' aggressive interactio ns towards the newly introduced females. These results suggest that fe male starlings use both aggressive behaviour (including song) and the solicitation of copulations to prevent their males from becoming polyg ynous. (C) 1996 The Association for the Study of Animal Behaviour.