This is a common fall migrant, which is found rarely in late summer and is accidental during the spring (late May and mid-June). Adult migrants are somewhat rare and so this species is not reliably found until the fall migration of juveniles, which begins in mid-August. The earliest southbound records are from early July, with only a few sightings until late July and most sightings of adult birds during the first week of August before the annual migration of juveniles commences sometime between August 10th and 20th. Daily numbers fluctuate greatly for this species though there tend to be two peaks of occurrence, one between August 25th and September 10th and the other from September 15th-25th. This likely coincides with a migration from Asia to the Yukon-Kuskokwim Delta and then a return migration back to Asia. Small numbers are regularly seen into early October and are usually still present mid-month. The exact timing of fall departure is not well known as they outlast birders present in the Pribilofs most years.