Wadden Sea report: breeding birds in the danger zone


Wadden Sea report: breeding birds in the danger zone

Press release

Two of the partners in CAPS, the Centre for Avian Migration & Demography and the Dutch Centre for Field Ornithology (Sovon) have analysed population change data for 54 bird species typically found in the Wadden Sea area of the Netherlands. The study was commissioned by the Netherlands Society for the Protection of Birds.

In addition to the number of birds counted, the study takes into account birth and mortality rates. All this information has been compiled by researchers from leading institutes, thanks in no small part to the involvement of a great number of tireless volunteers.

Cause for concern

New research methods have made it possible to present a much more accurate analysis of how well bird populations are doing, and will be doing in the future. The prospects for breeding birds look bleak, says the head of the Centre for Avian Migration & Demography and chief author of the report, Henk van der Jeugd:

"Our research clearly shows that many of the species that use the Wadden Sea as a breeding area are in decline. Earlier, it was mostly species that are dependent on tidal flats that gave us cause for concern, but now all species of breeding bird face declines in their population sizes."

The five species most affected are the hen harrier, the avocet, the short-eared owl, the Kentish plover and the oyster catcher. "When we look at the balance of birth and mortality, we know for a fact that the end of the decline is not yet in sight", warns Van der Jeugd.

Understand & predict

Millions of migratory birds come to the Wadden Sea every year. But despite the area's great international significance and protected status, its natural resources have been in decline for most of the past century.

To obtain an accurate understanding of the threats that bird populations are facing and how best to restore them to a healthy level, just counting birds is not enough. How many of the birds have chicks? How many die each year? Answers to these and other demographic questions may explain why one species is doing well while another is in decline.

This kind of 'integrated population monitoring', as it is known, will even help to look into the future. Which, in the case of the present study, is likely to bring further declines for most species of breeding birds...including even the spoonbill, which is currently doing very well.

Stronger together

To make more effective and timely measures for the protection of Wadden Sea birds possible in the future, integrated population monitoring should ideally be applied to a wider range of species and an area wider than just the Dutch part of the Wadden Sea. The Centre for Avian Population Studies has been founded to facilitate this process, says Henk van der Jeugd.

"The research is quite complex in nature and draws on a variety of databases, so close co-operation between a substantial number of partners is essential. That's what CAPS is all about. And let me stress that we don't just rely on professional researchers and scientists, but at least as much on ringers and other volunteers."

CAPS brings together the Centre for Avian Migration & Demography, NIOO-KNAW, Sovon, Radboud Unversity Nijmegen and the Dutch Society for the Protection of Birds. Assisting in its research are more than 9000 passionate volunteers. The Wadden Sea report was presented at the new partnership's inaugural symposium in Nijmegen on 6 November.

(Photograph of oyster catchers: Tom Voortman)


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