In Spain, the red-billed chough has recently expanded its range by utilising old buildings, with 1,175 breeding pairs in a study area. These new breeding areas usually surround the original montane core areas. However, the populations with nest sites on buildings are threatened by human disturbance, persecution and the loss of old buildings. Fossils of both chough species were found in the mountains of the Canary Islands. The local extinction of the Alpine chough and the reduced range of red-billed chough in the islands may have been due to climate change or human activity.