The most common Old World warbler in the Pribilofs, and the only Phylloscopus species to breed in North America, it is best looked for during the fall when it is nearly annual. However, a couple spring records from mid-June and a scattering of summer records from late June to late July indicate that it can be found at other times, with late June-early July likely the best period. During the fall when it is most expected, this species has been found across a large period from late August to October, while the majority of records are mid-late September, which is the best period to seek this species in the Pribilofs.
