Abstract
During the 35-year study period (1976-2010) the nesting distribution, population size and dynamics, as well as negative factors influencing the saker falcon population in western Slovakia were surveyed. After 1993 all of the nesting pairs have gradually resettled to the neighbouring agrocoenoses, previously used for hunting and wintering. This process was considerably influenced by management practices, especially the installation of 151 nest boxes on electricity pylons in lowland agrocoenoses in western Slovakia. Since 2009 all pairs have been nesting in agrocoenoses. During the last decade the number of nesting pairs has increased 145% and the nesting area of the saker has increased three-fold in western Slovakia. Data about 47 pairs and 345 nesting events were used to evaluate the population trend. The pairs raised 797 fledglings in 247 successful breeding attempts. Average success for all breeding attempts was 2.3 fledglings, and 3.2 fledglings for successful breeding attempts. The main reasons for losses during the study period are considered to be drastic changes in feeding and breeding habitats, illegal shooting and poisoning as well as nest robberies.