Nesting Use of Bridges by the Northern Rough-winged Swallow in the Sacramento Area

Abstract

Use of bridges and other transportation structures by the Northern Rough-winged Swallow has received little attention in scientific literature (Green 2005, De Jong 1996). Our recent observations of the species’ use of overpasses and elevated freeways (“bridges”) in urban Sacramento suggest that these structures provide nesting opportunities that may allow Northern Rough-winged Swallows to occupy urban areas that otherwise would be unsuitable for them. Better knowledge of the timing of nesting use of bridges may be useful to establish protection measures for maintenance and construction activities on bridges and adjacent lands. Bridges in Sacramento also are known to be occupied by several other hole-nesting species, which raises questions about species interactions and differences in nest site selection within bridges.