Foraging habitat selection, diet and nestlingcondition in Yellow Wagtails Motacilla flava breeding on arable farmland

Abstract

Capsule Yellow Wagtails showed seasonally variable foraging preferences, favouring field margin and crop habitats, although habitat availability did not influence brood productivity. Aims To identify key habitats and prey types for Yellow Wagtails in arable farmland, assessing the importance of foraging habitat availability in determining breeding productivity. Methods Intensive nest searches were conducted across six areas in eastern England over two breeding seasons. Focal nest watches were used to determine foraging habitat selection. Nestling condition was analyzed in relation to surrounding habitat characteristics and weather conditions. Diet was assessed using chick faecal samples. Results Wet ditches and tracks were favoured foraging habitats, together with crop fields used for nesting. Crop preference varied seasonally, with autumn-sown wheat preferred in May-June and potatoes preferred in July-August. Chick diet was dominated by flies (Diptera), although beetles (Coleoptera) were prevalent in early broods and damselflies (Zygoptera) in late broods. Weather and foraging habitat availability were poor predictors of nestling condition. Conclusion Our results highlight key microhabitats for Yellow Wagtails in arable farmland. The late-season avoidance of autumn-sown cereals implies that breeding season length could be limited in cereal-dominated areas. The provision of alternative late-season breeding habitats might represent an effective conservation strategy for this species. © 2009 British Trust for Ornithology.