Relationship between arrival date, hatching date and breeding success of the white stork (Ciconia ciconia) in Slovakia

Changes in the spring arrival dates of migrant birds have been reported from a range of locations and many authors have focused on long-term trends and their relationship to temperature and other climatic events. Perhaps more importantly, changed arrival dates may have consequences for the breeding dates of birds which strongly influence breeding success. In this paper we take the opportunity provided by a monitoring scheme of the white stork (Ciconia ciconia) to examine several features of the timing of arrival and breeding in relation to chick production in Slovakia during the period 1978-2002. First arrival dates ranged from 5(th) March to 30(th) April, and hatching dates varied between 26(th) April and 8(th) July. Generally, early arriving pairs started breeding earlier and a shorter interval between the arrival of the first partner and breeding, expressed here as hatching date, resulted in higher breeding success.