Abstract
In central Japan, Eurasian Kestrels Falco tinnunculus nest in railway bridges. The relationship between their nesting density and the characteristics of the nesting sites and of the habitat were investigated. Eurasian Kestrels were found to nest either solitarily or in loose colonies. For each breeding site, the nesting density per site was noted, as were the width, height and number of entrance holes, and the length of the bridges where nesting occurred. The total area of each habitat (grassland, cultivated land, other grassland, rice field, residential area, bare land, water surface area, forest, fruits garden) was calculated using GIS (Geographic Information System) software. The nesting density per breeding site was 0.14-0.99 pairs/km2, and was positively correlated to the total area of grassland and the bridge length. The results showed that the availability of suitable hunting grounds (grassland area) and nesting sites (bridge length) affect the nesting density of bridge-nesting Eurasian Kestrels.
