Despite significant efforts in the past thirty years to protect Dutch meadow birds, most Dutch bird populations in agricultural areas are still declining. The main causes of this decline are urbanization and agricultural intensification, which have created habitats where recruitment no longer outweighs the annual mortality. However, to counteract this decline, we must first understand the mechanisms by which urbanization and agricultural intensification actually affect meadow birds. For instance, does the problem arise during the breeding season — e.g., through low nest survival, high chick mortality, or poor condition of adult birds — or in a different phase of the life cycle — e.g., through mortality during the first year or constraints arising during migration and the boreal winter?

Such a comprehensive question requires a long-term study, taking place across a large spatial scale. In 2004, the University of Groningen launched its Black-Tailed Godwit research project in Southwest Friesland to try address these questions in one of the strongholds of this rapidly declining meadow bird species. Since 2012 we have been using UvA-BiTS transmitters to help us identify those habitats used by Black-tailed Godwits throughout their annual cycle and how the food resources available to godwits in these habitats may influence both their migration and the timing of their reproductive efforts. We are especially interested in the transition from staging sites in Spain and Portugal to the breeding season in the Netherlands.

Our initial findings suggest that Black-Tailed Godwits no longer properly time their reproductive events with the local habitat phenology and that this may be the most important cause of their decline. Our goal is to create a mechanistic understanding of how these two periods of the annual cycle are linked in order to provide farmers and land managers with the information they need to properly manage Black-Tailed Godwits.

Contact persons, funders and participants

Nathan Senner n.r.senner@rug.nl Rijksuniversiteit Groningen

Theunis Piersma theunis.piersma@nioz.nl Royal Netherlands Institute for Sea Research

Global Flyway Network