Breeding success and post-fledging survival in the ChoughPyrrhocorax pyrrhocorax

Abstract

The breeding success and post-fledging survival of Choughs has been investigated on the island of Islay, which holds one of the densest breeding concentrations of Choughs in the British Isles. There was no significant difference in average young production per nest between birds nesting in buildings and those at the more traditional cliff sites. The overall average number of young fledged per nest per year was 2.02, which is lower than has been reported in other areas, despite the comparatively large clutch size of Choughs on Islay. From observations of marked birds, we estimated survival to be at least 71% in the first year of life and 74% in the second year, much higher than previously published estimates.