in most migratory north american passerines the preformative and prebasic molts occur largely on the breeding grounds in late summer following nesting (Pyle 1997), but there are some exceptions to this pattern. some species initiate molt on the breeding grounds, then suspend it over migration, before resuming and completing molt in the nonbreeding range (Howell 2010). Within a species, populations may differ by latitude in the timing and location of molt, with southern populations breeding and molting earlier than northern ones (Pyle et al. 2018).