SEEN - SE European Bird Migration Network
Do White Storks in the Czech Republic breed earlier? An analysis of ringing data from last 40 years
Cepák J.1, Albrecht T.(2) and Skopek J.(1)
1) Bird Ringing Centre, National Museum Praha, Hornoměcholupská 34, 102 00  Praha 10-Hostivař, Czech Republic
2) Academy of the Science, Department of  Vertebrate Biology, Květná 8, 603 65 Brno, Czech Republic

In the Czech Republic, the White Stork is a regularly breeding species (about 800 pairs in 2003).16 311 individuals were ringed in the Czech Republic and Slovakia in 1964-2002. We analysed basic ringing data (ringing date, number of hatchlings) obtained from 2432 nests in the Czech Republic in this period.
Number of hatchlings per nests slightly increased within the last 40 years. Ringing data show that the Storks are currently ringed about a week earlier than in the 1960s. This result is supported by the analysis of the recoveries of young less than 100 km from the nest, which show that the fledging date is earlier too. We suppose that there has been a change in the timing of breeding (based on the ringing date) - similar as in other bird species in Europe.
These results show that common ringing data are valuable and can be used for further analysis  (long-term trends in reproductive characteristics and their comparison with ecological factors (climate, food availability etc.).
Created by Pronetix 2006