The most common breeding auklet in the Pribilofs, this species typically arrives at the islands cliffs in mid-late April. They often arrive en masse and are present in the thousands by May, with the peak breeding numbers occurring from late May to early July. The estimated breeding population for St. George Island is 125,000 pairs, the estimate on St. Paul Island is 10,000-20,000 pairs, and the breeding populations on Otter and Walrus Islands are in the hundreds of birds. Nesting is typically completed during July and into early August with a steep decline in numbers shortly after that with the breeding colonies nearly devoid of birds by August 15th-25th. This species is a rare sight by the end of August with only sporadic sightings at sea through the rest of the fall. Large numbers occur offshore during the late fall and winter and occasionally are seen from land during storms or after die-offs. Their winter abundance is also controlled by the winter sea ice with more birds present in open water.
