Fig. 1.

Spring departure dates of immature American redstarts and the δD of their first breeding attempt. (A) Immature redstarts wintering in mangrove forest (red circles) tended to depart early on spring migration and migrate comparatively short distances, whereas redstarts in second-growth scrub (blue circles) were more likely to depart later and migrate longer distances. (B) As a consequence, immature birds from mangrove made their first breeding attempt (mean ± SE) in southerly areas, whereas those birds from scrub bred at more northerly sites.