Axial migration routes in Cormorants Phalacrocorax carbo passing through or wintering in Switzerland.

Sightings of colour rings were used to study the origin of wintering and migrating Cormorants in Switzerland between 1977 and 1988. The recorded individuals originated from all parts of the breeding range of sinensis and included also two carbo birds from Norway. According to the recovery rate of each colony/colonies most birds present in Switzerland belong to the Danish population. Significant lower recovery rates were found for eastern Germany, Poland and Sweden, while that for The Netherlands was comparable to western Denmark. These data suggest a west-east axial migration pattern, in which Cormorants predominantly disperse SSW from their breeding areas.

Reymond A. & Zuchuat O, ARDEA 83 (1): 275-280.