Mew Gulls are not annual in the Pribilofs. They have however established a pattern of somewhat regular occurrence, showing up every two or three years. Some years many individuals appear, generally either between mid May and mid June or mid July through the end of August. These individuals are most often found in amongst flocks of resting kittiwakes, either at the Salt Lagoon or the sand spit at Big Lake. Two subspecies of Mew Gull regularly occur in the Pribilofs, with the American formbrachyrhynchususually outnumbering the Asian formkamtschatschensis. The separation of these two subspecies is tricky. The Asian birds are generally larger (useful only if both subspecies are present) with more black in the outer primaries, a longer bill and blockier head shape than the American birds. If possible photos should be obtained of any putative Kamchatka Gull, so that assorted Larophiles can debate its identity for years to come.