Figure 2.

Variation in innovative PSP with respect to age (whether birds were in their first winter or were adults), and the winter assays were conducted. p-values were taken from post hoc tests on data for individual winters, with all main effects in the model (time of season, age, sex, EB and natal origin). Numbers in bars refer to sample sizes. Dark bars, number of birds that solved the foraging task; white, numbers that did not solve.