Abstract
The Eurasian Tree Sparrow Passer montanus is common in both urban and rural areas in Japan and often nests in spaces of man-made structures (e.g. electric transformer boxes, under eaves). Therefore, differences in the designs of such artificial structures and their spatial distributions between urban and rural areas could influence the breeding ecology of the Eurasian Tree Sparrow. In this study, we compared (1) nesting site, (2) number of breeding attempts in a season, (3) nest re-use and (4) spatial distribution of nests, of tree sparrows between urban and rural areas. In our urban study site, birds nested most frequently in spaces in transformer boxes on telephone poles. At our rural site, birds preferred to nest under the eaves of houses. Differences in ecology were also detected between urban and rural sites. There were three breeding peaks in the urban area, but two in the rural area. Nest reuse was more frequent in the urban area than in the rural area. The spatial distribution of nests was random in our urban study site, but aggregated in our rural site. These differences may contribute to differences in the strength of individual interactions and reproductive success between urban and rural sites and could help explain the differences in the abundance of this species between environments.
