Cooperative breeding by Alpine accentors Prunella collaris: Polygynandry, territoriality and multiple paternity

The composition of breeding groups, territoriality, parentage and parental care were examined in a population of Alpine Accentors Prunella collaris in the Swiss Alps. Five (1993) and six (1994) breeding groups were located on a south facing hillside between 2500 and 2860 m above sea level. 3-5 males cooperated in the defence of their group territory, wherein 2-3 females each held an exclusive territory (separate nesting polygynandry). Males competed for access to fertile females within their group territory. The females copulated promiscuously with all or several males within their breeding group. The alpha- and beta-males had more access than other subordinate males. They combined frequent copulations and mate guarding as types of paternity guards. The female performed most of the parental care. Usually, 1-4 males helped feeding the young. Results of DNA-profiling showed that members of one group were seldom closely related. In three out of five sampled broods, multiple paternity occurred with up to three males siring offspring within one clutch.