Nesting of the Eurasian Tree Sparrow on utility poles

Abstract

The Eurasian Tree Sparrow Passer montanus is one of the most common urban avian species in Japan; it predominantly nests in artificial structures. Humans act as ecosystem engineers, unintentionally providing nest sites for these birds. Birds nesting on utility poles can cause electrical power failure in the surrounding area; thus, such nesting behavior may impose risks and losses on the human community. While it is necessary to prevent sparrows from causing power failure through nesting on utility poles, this is in conflict with the global trend of promoting biodiversity in cities. Our aim was to obtain basic information concerning nest site selection on utility poles by Eurasian Tree Sparrows, in order to find ways for humans to coexist with this species. Our main results were as follows: (1) sparrows built nests in arms, the most common material of power poles; (2) the number of nests per utility pole differed between regions because different power companies use distinct arms; and (3) even within the same region, the number of nests on utility poles differed between urban and suburban areas. For humans to coexist with Eurasian Tree Sparrow, while supporting their population, it may be necessary to provide the birds with alternative nest-sites and to preclude them from nesting on power poles.