We examined the avifauna in and around the Nagasaki Airport, and investigated the behavior and food habits of the Black-eared Kite, Milvus migrans, which roosted in Usu-jima Islet near the airport from June, 1977 to March, 1979. The results obtained are as follows: 1. Sixty-two bird species belonging to twenty-six families were observed in and around the airport. In the course of census, we found wintering of the American Golden Plover Pluvialis dominica from 1977 to 1978, and the Chinese Great-grey Shrike Lanius sphenocercus on January 10, 1978 which had been rarely observed in Kyushu, Japan. In the airport the dominant species were always the Skylark , Alauda arvensis, and the Tree Sparrow, Passer montanus. 2. The Black-eared Kites left the roost in Usu-jima early in the morning, and flew to the feeding area, but some kites remained on and around Usu-jima all day long. The maximum number of kites is highest between September and November, and they decreased markedly in December; they increased again from January to February, but only a few individuals were observed between March and July. These changes in abundance of kites probably reflect their migratory movements. 3. Between September and October many kites moved in a wide area, but less so in other months. Especially in December, all kites lived within a very restricted area. Accordingly, the extension and reduction of the daily movement seem to relate to the feeding area, which changes with fluctuations in kite's abundance. We found another roost in Osaki Peninsula, north to the Nagasaki Airport, and there seemed to be other two roosts. The kites roosting here seemed not to move so far. Since there is abundant food for the kites along the coast, it seems enough for their existence to feed within a narrow area. 4. Fishes were most abundant as food items of the Black-eared Kites and a kind of gobies, Chaeturichthys hexanema, occupied the highest percentage of them, being followed by insects. Especially in October, a number of kites gathered at the airport in order to feed on locusts which inhabited the grassland, so that the ratio of kites with stomachs including insects temporarily increased. Other foods detected were the kite (probably fed after death), skylark and a kind of pill-bugs, Armadillidium vulgare.