Holmes 1961 Erola alpini Molt 12 Oct Juveniles can be distinguished by the buffy edging the upper wing coverts + by the non-molten rump parts which appears to have feathers with rusty or at least "lightened" edge - as opposed to the adult gray color. The chin is considerably darker - a bold t across the throat. Throat / jaw: dash soots gray with white chin - no ruddy patch post. Tye. Underwing coverts at bend / wing - are dark for leading 2-3 rows (which in adults only a faint lightened gray is observed). One jun showed the 2-3 outer rows (ant) of coverts to be non-molten - as well as 2-3 inner rows - but those whether were gray (# ).