Food Habits of the Black-eared Kite, Milvus migrans Zineatus, in Nagasaki Airport and Its Adjacent Areas

Abstract

Food habits of the black-eared kite Milvus migrans lineatus were analysed based on the stomach contents obtained from 241 kites, which were shot to reduce strike damage to aircraft or hit by aircraft at Nagasaki Airport, Nagasaki Prefecture, during the five-year period from 1977 to 1981. Most of the samples were collected in summer and autumn when the number of the kites was large. The kites fed mainly on fishes and insects in this period : especially in August and September, the former was their main diet. This fact was presumed to be related to the following two factors : 1) a mass death of fishes due to both an outbreak of a red tide and a lack of oxygen dissolved in bottom waters, and 2) abandonment of a quantity of worthless fishes, which thronged into well-conditioned environments owing to deterioration in water quality and consequently became easily captured by fishermen. In October and November the kite chiefly preyed on locusts. During this period, a large number of them inhabited green belts in the airport ; thus the kite seemed to eat preferentially locusts which were easy to catch. It was concluded that the black-eared kite fed on prey animals obtained easily according to habitats and/or seasons