INFLUENCE OF WEATHER ON TIME ALLOCATION OF UNPAIRED PIED FLYCATCHER FICEDULA-HYPOLEUCA FEMALES

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