© Marcel Burkhardt
Knaus, P. (2010)
The distribution of breeding birds in Switzerland in the 1950s compared to the present situation.
Bird Census News 23: 41–47
A project was launched to document the distribution of breeding birds in the 1950s in Switzerland. This historical atlas allows direct comparisons with the two atlases 1972–1976 and 1993–1996. As many original records as possible at a national level were compiled from notebooks and different archives as well as via standardised interviews with 56 field ornithologists of the older generation. The country was divided into 467 atlas squares (10 x 10 km), but convincing comparisons of the distribution in 1950–1959 with the two published atlases are in general restricted to the Swiss Plateau. Our data document that in the 1950s several farmland and wetland species were widespread across the whole Plateau, but since then lost a considerable part of their range or disappeared completely. On the other hand, we also report on range expansions for some species.