Roads have been shown to affect numerous bird species, via mechanisms such as collisions and noise disturbance. Most of the studies behind these findings, however, have been relatively small-scale and little is known of the wider impacts of roads on bird populations. Using Great Britain as a case study, we explore the relationship between roads and the spatial distributions of bird populations. We model bird count in relation to road exposure whilst accounting for the effects of other factors known to affect bird populations. We also account for potential impacts of roads on detectability. We show populations of several species to be increased or decreased around roads and highlight the serious potential of roads to cause large-scale modifications in bird communities. We also demonstrate significant impacts of roads on detectability of birds in surveys and suggest that future studies on the effects of roads on bird populations should account for this.