Figure 5
From: Reproductive responses of birds to experimental food supplementation: a meta-analysis
Effect of the background level of resources on reproductive responses of birds. Effect of the background level of resources in the environment (higher/lower than average) on variation in (a) three bird reproductive parameters, including (b) laying date, (c) clutch size and (d) breeding success in response to food supplementation experiments. Mean effect sizes (Hedges d) and 95% confidence intervals are presented, with sample size (number of experiments) above bars.