Glaucous-winged Gulls are the dominant large gull species in the Pribilofs for the majority of the summer months. In early spring, only a hundred or so individuals are typically around the island, but by late summer, the roosting flocks can number into the low thousands. Searching through these motley throngs of often very scruffy looking Glaucous-winged Gulls can prove rewarding, Even if a rare species is not detected the variability of this species is astounding, and is likely augmented by birds which upon close examination seem to exhibit hybrid characteristics. As of 2005, this species does not regularly breed in the Pribilof Islands. Apparently as recently as 20 years ago there were very few large gulls around during the summer, and USFWS is concerned that if these birds begin to breed (Walrus Island is the most likely sight) that they will become a major predator on the island’s cliff-nesting seabirds. If visiting naturalists notice any predation events by Glaucous-winged Gulls while on the island please bring it to the attention of your guide who will notify the proper authorities.