Figure 4.

Variables that explain the difference between years in the contribution of the earliest 10% of males to moult to population growth. The graphs depict the capacity of each of the three explanatory variables to explain the residuals of the models containing just the other two variables. (a) The probability that males 4 years or older moulted early. (b) Whether early moulting birds were affected by one or more pre-breeding mortality events. (c) The proportion of territories with at least one helper.