Spaced out nests and predators: An experiment to test the effects of habitat structure

The effect of nesting density on predation rate was studied in relation to habitat using artificial Blackbird nests placed at high, medium and low densities in three habitat types: woodland, woodland edge and farm hedgerow. The results showed that predation was lower in woodland than in woodland edge, which in turn had a lower predation rate than farmland. There was evidence of increasing predation rate at higher nesting densities in both woodland edge and farmland, Therefore there appears to be a potential cost to nesting at high densities in farm hedgerows and to a lesser extent woodland edge which is likely to be facilitated by enhanced 'edge effects' in those habitats.