Aging Passerines using Molt limits

American Robin ASY Male -no molt limit -broad feathers with dark shafts

American Robin SY Male -molt limit -narrow, “weaker” primary coverts SY Female -molt limit -narrow, “weaker” primary coverts

ASY SY Broad primary coverts with dark shafts. Broad greater coverts With no molt limit. Narrow, weak primary coverts with brown shafts. Molt limit within greater coverts. SY Retained coverts Replaced coverts

Yellow-rumped Warbler ASY Male -1 molt limit Alt plumage (greater coverts)

Yellow-rumped Warbler SY Male -2 molt limit Alt plumage (greater coverts and retained first year feathers)

Indigo Bunting The Test Age? ASY Age? SY How do you know? No molt limit Age? SY How do you know? Clear molt limit