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Résumé :
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The breeding success of Skylarks was studied as a part of the pilot and development project Nature Conservation Farm Brodowin\'. The project aims to identify conflicts between modern large-scale organic farming and nature conservation, to develop suitable solutions and to investigate the effects on plant production and business management. In this context, a total of 132 Skylark nests were monitored and the fate of 43 chicks was studied using radio tracking. Predation, for instance by carnivores, rodents and raptors, accounted for the majority of nest losses. Further losses occurred due to farming activities. If only predation was taken into account, the survival rate of nests was 46% or 1.4 chicks per nest. The inclusion of losses due to mowing and other farming activities resulted in a slightly lower productivity of 1.1. Thus, nest survival is comparatively high and indicates a potentially high quality of the investigated fields. The survival of 21 chicks outside the nest until fledging was only 19% and therefore lower than expected. Again, predation was the most important factor affecting survival. Since this is the first study on survival of Skylark chicks outside the nest the consequences of chick losses for the population remain unknown. A population model including nest fate, number of breeding attempts, chick survival and further data from 2004 is needed in order to assess whether the population studied is self-sustaining.
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