An uncommon breeding species, the first spring arrivals are typically found during mid-May (earlier records do exist) with small numbers of migrants and local breeders seen through late August in most years. This species is most easily found the last week of May and first week of June when migrants and breeders overlap, while the delineation of migrants and local breeders is not well known (nor are records consistently kept for this species,) though numbers seem to have settled into their summer numbers by mid-June when the few pairs that do nest on the islands often become difficult to find. This species has only been confirmed, or presumed, breeding on St. Paul Island and St. George Island within the Pribilofs as the lack of freshwater habitats on the other islands likely keeps them from attempting there. The first confirmed breeding record for the Pribilofs was on St. Paul Island in June 1985. Appropriate habitat is still sparse on St. Paul Island, with a total of perhaps three to eight total pairs breeding on the island in an average year and smaller numbers on St. George Island. Southbound arrivals and locally fledged birds are typically not seen until late July, with increased numbers found until mid-August when most individuals have passed through or left the Pribilofs. Records into late August and early September are very rare.
