Habitat structure is thought to affect the time and energy budgets of foraging birds through impacts on mobility, prey accessibility, prey abundance and predation risk. Many studies. particularly those with direct relevance to field ecology, cannot disentangle these different effects. This thesis decouples the effects of sward structure on mobility, prey accessibility and predation risk, whilst controlling for prey abundance, for the socially foraging starling Sturnus vulgaris in agricultural grasslands. I use an experimental approach throughout, exposing wildcaught starlings to variations in prey accessibility and predation pressure using a series of integrated studies.