States, a black-tailed gull was spotted from Burlington, Vermont, in October 2005. The species has been spotted in Illinois several times. Ecology The black-tailed gull feeds mainly on small fish, molluscs, crustaceans scraps and carrion. A study analyzing the identifiable parts of gull excreta in Korea found that 19.1% consisted of the remains of fish, 3.3% of crustaceans, and 3.3% of land insects. The species often follows ships and commercial fishing fleets. It also steals food from other seabirds. It is a colonial nester, with colonies forming in mid-April. 2–3 eggs are laid by early June. Incubation lasts approximately 24 days. Black-tailed gulls use a variety of voice signals and are known to use more than 10 different sounds for communication. Young can recognize their parents from their voice and visual stimulation between 10 and 15 days after hatching, and can also distinguish between siblings and non-siblings. Alarm calls are alert signals that warn of predators or danger. Aggressive calls accompany attacks on predators. Contact calls are signals used for intra-specific communication. The most commonly heard cat-like sound ("mew call") is a part of the contact call, and is frequently used, such as when returning to the nest after taking food, alternating the role of the mating and nesting, taking care of the young, collective flight, etc. The sound of a young gull begging for food and the sound of a female during mating are also included in the contact call. Images References External links Black-tailed Gulls at Kabushima – official site Black-tailed Gull in California Black-tailed Gull information and Photos in California Video showing the gulls of Kabushima Video showing the gulls of Kabushima black-tailed gull Birds of East Asia Birds of China Birds of Japan Birds of Korea Birds of Manchuria black-tailed gull black-tailed gull