|ring area||The Netherlands, near Delfzijl|
|observations||804, of which 122 are captures|
|ringed in||1999 to 2001|
In the years 1999-2001 Oystercatchers breeding on the havenschermpier in Delfzijl were caught and individually colour-marked by the former RIKZ to study how patch and prey choice impacted the intake of toxic chemicals. This population study has been continued by Sovon and both adult breeders and nearly fledged chicks are marked.
Observations of these marked animals allow us:
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.