The only passerine species that breeds entirely within Asia that is regular during both the spring and fall in the Pribilofs, it may be seen at almost any time on the islands from May to October. During the spring this species is most commonly seen during the final week of May, though records span from mid-May to mid-June. Sightings during June are less regular with only a handful of records after the first week of June, but there are a few summer records from late June to early August. Fall migrants have not been recorded prior to the first week of September and are regularly encountered by mid-September with a fall peak from September 20th to October 5th. Migrants have been noted into late October and this species likely remains further into the fall and winter during some years; however, only a single winter record exists.
