Nest survival in the Reed Bunting Emberiza schoeniclus in fragmented wetland habitats: the effect of nest-site selection

Abstract

Nest survival in fragmented wetlands is usually affected by micro-habitat variables. The main aim of the study was to investigate the factors affecting Reed Bunting Emberiza schoeniclus nest survival in wetland habitats within a mosaic Central European land-scape. In total, we monitored 95 nests on five separate fishponds in South Bohemia, Czech Republic during a six-year study between 2002 and 2007. In order to determine the effects on nest survival of nest site characteristic, the first egg laying date and nest age, we estimated daily survival rate (DSR) and built models using program MARK. DSR was significantly higher in nests located in Reed Canary Grass Phalaris arundinacea and tall vegetation Cattail Typha latifolia and Common Reed Phragmites australis than in sedges Carex spp. Surprisingly, expanding Reed Canary Grass was occupied later in the breeding season and likely less preferred vegetation type than sedges. Structure of sedge tussocks changed due to eutrophication and likely lost its suitability as quality microhabitat of the nest site. Furthermore, we found mild support that DSR increased with the distance from the nearest tree and that the lowest DSR was between 19th and 20th day of the nesting cycle, close after the hatching of the nestlings which can attract potential predators. These findings could indicate the importance of birds as predators on Reed Bunting nests. Nest site selection appears to be a display of anti-predator strategy in the Reed Bunting.