Ornithological research was carried out near the airport Bratislava-Ivanka pri Dunaji, Czechoslovakia. Black-headed gull Larus ridibundus reacted to the start of the plants work by an increased quantity and, as distinct from the 2 preceding years, they were present all the year round, including the summer months. With progressing construction works on the plant, neighbouring biotopes were destroyed. This became manifested in a decrease in abundance of 15 species predominately bound to tree and shrub vegetation. The incidence of another 94 avian species was not affected by construction works.