Why are oystercatchers in the Netherlands declining?

Running period: 

How do human impacts such as climate change affect bird populations, and in particular the oystercatcher? As part of the new Centre for Avian Population Studies, the Netherlands Institute of Ecology (NIOO-KNAW), Radboud University and Sovon (Dutch Centre for Field Ornithology), have launched project CHIRP: 'Cumulative Human Impact on biRd Populations'.

CHIRP aims to relate human impacts in both breeding and
winter areas to population dynamics.

The Eurasian oystercatcher has been in rapid decline in the Netherlands for more than 25 years. It's also been thoroughly studied in the past, making it a perfect 'test case' for project CHIRP.

CHIRP aims to develop a modelling framework that integrates how various human impacts (e.g. climate change, agriculture, mining, fisheries) that act at different spatial and temporal scales affect bird populations. It will use this knowledge to identify mitigation actions that will minimize the impact of human activities, and to develop the best conservation strategy for helping species recovery.

The project will combine new field data collection (e.g. using GPS-trackers to assess the impact of disturbance on birds) with the development of new hierarchical models that link eco-physiological, demographic and migratory processes.

Field data is collected throughout the year to evaluate the effects of human impacts in both winter and summer.

In winter, oystercatchers are equipped with GPS-trackers near the militairy airforce training grounds at the Vliehors. in order to study the direct and long term effects of disturbances.  The large scale consequences of disturbance are then assessed by incorporating the disturbance effects in simulation models that predict condition and survival of wintering oystercatchers in the Wadden Sea and Delta.

In summer, drivers of reproductive success, e.g. habitat and predation risk, are assessed for inland breeding grounds. Furthermore, body condition in winter is related to reproductive success by monitoring breeding birds whose body conditions were measured during previous winter catches.

On Ameland, the oystercatcher population will be monitored to study the impacts of soil subsidence on reproductive success.