Oystercatcher

Details

Every year, several hundred Oystercatchers are individually colour-marked in the Netherlands and Schleswig-Holstein. Both adult breeders and nearly fledged chicks are marked. Some of these animals feed in places, like oyster beds, where their colour rings are subject to heavy wear and become quickly unreadable. If possible, such animals are fitted with an engraved ring on the tibia, where it is more difficult to read, but will not suffer from heavy wear.

Observations of these marked animals allow us:

1. To estimate (annual) survival and investigate which factors impact survival (age, quality breeding habitat, quality wintering habitat, winter weather).
2. To determine connectivity between breeding areas and wintering areas (where do Oystercatchers that breed in a certain area spend the winter and vice versa) and the site fidelity to these areas.
3. To determine where fledged Oystercatchers settle as breeders, i.e. natal dispersal. Do they settle in the area where they grew up? If not, does the new habitat resemble the natal habitat?

This knowledge is very important to identify the causes of the dramatic population decline of this longlived species (current record 46 years) in the Netherlands : due to an annual decrease of 5%, the population has more than halved since 1990.

This project is a cooperation between NABU, NIOO-KNAW, Sovon Vogelonderzoek Nederland, Stichting Onderzoek Scholekster (SOS), RuG en WMR.