P. DeBenedictis 1965 Xema sebini: 28 July. Barrow, Alaska - The Black-headed gull, with vocalization probably rather close to L. philadelphia. The forward was seen twice given by one bird defending a nest island and the bill tossing were given by both member of the pair one after another bird passed by. or the water birds in forward position set low so that the open wing leading edge fricled the water. The birds were quite aerial and little ground display seen. I had the impression that some of the birds in the colony were not breeding and an anomalous plumage - a bird with adult wings but a black-tipped bill was seen. One or two lone birds seen away from the colonies. Bob induced a distraction display from one bird be approached.