| The Asiatic subspecies of Sitta europaea form an independent group of races which differ from the European subspecies by their smaller size and bill shape. Based on substantial samples of most of these taxa the present revision distinguishes 13 recognizable subspecies in the group. We remove from the group the subspecies arctica Buturlin, 1907, which is the most distinctive of all the Asiatic forms, because there is a zone of sympatry between this and S. e. baicalensis Taczanowski, 1882, where hybrid individuals may occur but if so must be extremely rare. We therefore support the elevation of arctica to full species level. |
