SPACED OUT NESTS AND PREDATORS - AN EXPERIMENT TO TEST THE EFFECTS OFHABITAT STRUCTURE

The effect of nesting density on predation rate was studied in relatio n to habitat using artificial Blackbird nests placed at high, medium a nd low densities in three habitat types: woodland, woodland edge and f arm hedgerow. The results showed that predation was lower in woodland than in woodland edge, which in turn had a lower predation rate than f armland. There was evidence of increasing predation rate at higher nes ting densities in both woodland edge and farmland, Therefore there app ears to be a potential cost to nesting at high densities in farm hedge rows and to a lesser extent woodland edge which is likely to be facili tated by enhanced 'edge effects' in those habitats.