Figure 1.

Relationship between female density at birth and the plasticity (slope) of a given cohort's breeding date–Southern Oscillation Index (SOI) interaction for song sparrows on Mandarte Island, British Columbia between 1975 and 2006. Cohort slopes were extracted from the best linear unbiased predictors (BLUPs) of the random effects from the top linear mixed-effects model (table 1b). BLUP estimates for the sample are centred around mean zero (25 out of 29 cohorts had a positive slope for average breeding date regressed against the SOI).