Birds are commonly used as tools in environmental monitoring. Bird population changes were studied during construction of the new Vuosaari harbour in 2001–2011. The aim of the monitoring programme was to determine the impacts of road construction on bird populations in the Österängen agricultural area (Helsinki, Finland). Our results indicate that the number of species and territories increased during and after construction, with more territories located closer to the road than before the road was constructed. Thus, road construction resulted in a momentary positive impact on bird populations. New grass and bush areas and even large rocky outcrops clearly benefited some species such as the threatened northern wheatear. The bird populations declined slightly several years later, probably as a result of habitat succession.