Alpine Swift (Apus melba) Science Article 10
Since the first record of two birds in 1952 the colony of the Alpine Swift in the city of Freiburg im Breisgau (SW Germany) has increased to at least 259 individuals in 1999. From the beginning the population has been monitored and protective measures have been taken, a work that has been intensified since 1990.
Matthias Schmidt, Naturschutz sudl. Oberrhein 3: 35-44.