Pigeon guillemots are attractive black and white alcids that winter in good numbers around the Pribilof Islands. The bulk of the Pribilof birds head north towards their breeding grounds along the Alaskan coast by the end of May. Scattered individuals, often first year birds will sometimes linger around Saint Paul well into the summer, although by late June even these lingering birds will usually clear out. By early September the fist fall birds will reappear as they press south towards perennially ice-free waters. Most birds seen during the tour season are already dressed in their dapper black and white breeding plumage, but some individuals remain in their largely white basic plumage and others are heavily molting creating a patchwork of black and white across the breast. Good places to watch for Guillemots include Marunich, Reef Point, Southwest Point, and the perimeter of Northeast Point. The very similar Black Guillemot has occurred in the Pribilofs multiple times, and should be looked for whenever one is confronted by Pigeon Guillemots. The most reliable way of separating the two species is to look for the underwing color, which is gleaming white in Black Guillemots and a dusky gray on Pigeon Guillemots. This color is often visible in flight, and sitting birds on the water will often flap their wings, revealing their true colors.