Influence of weather on time allocation of unpaired Pied Flycatcher Ficedula hypoleuca females

Abstrakti

Unpaired Pied Flycatcher (Ficedula hypoleuca) females were radio-tracked for 1-4 days in four nest box areas occupied by several singing males. Female behaviour was divided into three categories and the time spent on each one was used to construct a daily activity budget for these birds; (1) mate sampling (visiting male territories), (2) foraging, and (3) other activities (mainly moving around) . On average, 14% of tracking time was used for mate sampling, while over 60% of time was devoted to foraging . When the ambient temperature of the tracking day or the day before it was high, females spent more time on visiting the territories of males. Other weather variables correlated also with sampling activity, probably because they were intercorrelated. Observed foraging time was not related to weather conditions, unless females that were moving around were actually seeking food patches. This relationship between mate sampling and air temperature indicates that during adverse weather, the females concentrated on maintenance and refrained from mate sampling. Heavier females tended to spend a greater proportion oftime on visiting males than the lighter ones did, which may be due to an increasing interest for pairing when they begin to move into the reproductive phase