Telemetry of Red Foxes and Raccoon Dogs as predators of breeding birds in the Wadden Sea



Schleswig-Holstein Agency for Coastal Defence, National Park and Marine Conservation – National Park Authority


Dr. Philipp Schwemmer


Populations of many breeding bird species in the Nationalpark Wadden Sea are decreasing dramatically and continuously since several years. Reasons for those declines are manifold. One important cause is doubtlessly the bad breeding success of many ground breeding bird species. Strongest declines of breeding pair numbers and the worst breeding success can be found in the saltmarshes along the mainland coast. As an example, population numbers of Eurasian Oystercatcheres (Haematopus ostralegus) have been declining dramatically in 12 selected monitored saltmarsh sites along the mainland coast since the end of the 1990s. One essential factor for the ground breeding birds in the Nationalpark Wadden Sea is the strong predation pressure along the mainland coast. The most important predator is the red fox (Vulpes vulpes) and nowadays also the invasive raccoon dog (Nyctereutes procyonoides). Naturally, islands and Halligen are the predator-free sites in the Wadden Sea. However, there are numerous hints in recent times, that those sites are being visited regularly by foxes which leads to severe impairment of ground breeding birds. The low breeding success in the saltmarshes along the mainland coast is also very likely caused by predation of terrestrial mammals.

Project goals:

To unravel the movement patterns of foxes and raccoon dogs along the Wadden Sea coast and to evaluate the impact of those terrestrial predators on birds in saltmarshes along the mainland coast (and particularly on islands and Halligen), both species will be caught along the Wadden Sea coast and equipped with GPS-collars. The aim of the study is to study the activity patterns of foxes in different habitat types along the coast (i.e. conservation polders, farmed areas, pastures, saltmarshes as well as islands and Halligen). The results of this pilot project can provide a first baseline for a management concept.