Number of breeding bird species
In 2013–2016, Switzerland accommodated 210 species of breeding birds. Between 8 and 140 species were found per atlas square. At low and medium altitudes, between 40 and 50 breeding bird species occupy each kilometre square; above the tree line, significantly fewer species occur.
In 2013–2016, 210 species bred or attempted to breed in Switzerland. A further six species bred in neighbouring countries close to the Swiss border, but still within the atlas perimeter.
Number of species per atlas square in 2013–2016
The number of breeding bird species found per atlas square (10 × 10 km) ranges from eight (65/15 Finsteraarhorn) to 140 (55/13 Vouvry). The most species-rich atlas squares are located all over Switzerland. In many cases, these squares contain nature reserves (mostly wetlands) and/or span a large altitudinal gradient. Besides atlas squares in the Rhone and Rhine Valleys, areas around Lakes Neuchâtel, Thun, Constance, Zurich and Lago Maggiore are particularly rich in species. When comparing the different biogeographical regions, the Jura comes out on top with an average of about 100 species per atlas square. On the Central Plateau and in the northern Alps, 97 species were found on average per atlas square, and 85 in the central Alps. The southern Alps present a mixed picture. In general, species richness declines with increasing altitude. The lowest species numbers are found in atlas squares high up in the mountains.
Number of species per kilometre square in 2013–2016
The highest species numbers per kilometre square (1 × 1 km) are found in lowland wetlands. Based on the modelled data and the point maps, 70 species of breeding birds per kilometre square occur in the Fanel BE/NE on Lake Neuchâtel; other wetlands accommodate a similarly high number of species. More than 50 species per kilometre square are found in the Ajoie JU and in Lower Engadine GR. Squares in the Jura and on the Central Plateau generally hold 40 to 50 species in areas without wetlands. In southern Ticino, the number of species per kilometre square tends to be lower than in the lowlands north of the Alps. Urban centres such as Zurich or Basel show somewhat lower species numbers than the surrounding area. Above the tree line, species richness declines rapidly.