Female settlement in marsh wrens: is it affected by other females?

Summary The influence of resident females on the settling patterns of subsequent females was examined for marsh wrens (Cistothorus palustris). Proportionally more females responded to a playback of a female intruder during the pre-laying stage than during the laying and incubation stages. The strength of the response was also greatest during pre-laying and laying stages (Table 1). Female wrens did not settle randomly with respect to the presence of other females, but rather settled with bachelor males more often than predicted by chance (Table 3). Female settlement within territories was more asynchronous than settlement between territories. An attempt to fit these data to two models of female settlement suggested that prospecting females were not displaced by residents, but rather avoided settling with mated males (Table 3). Females within territories were also more dispersed than predicted by chance, a pattern that may be enforced through aggression on the part of the resident female. Staggered settlement reduces the overlap in nestling stages of harem mates and so may be a strategy to reduce competition for resources at this critical stage.