Bureau Waardenburg
Varkensmarkt 9
4101 CK Culemborg
the Netherlands
T: +31 (0) 345 512710
email buwa

Voedseltekort voor visdieven op de Kreupel
Your location:

Food shortages for common terns

In the Netherlands, 2009 was the year of the common tern (Vogelbescherming Nederland and SOVON Vogelonderzoek Nederland). It now appears that for the common tern, that 2009 was a poor year. A few years earlier saw the creation of the island de Kreupel in the Dutch IJsselmeer, which had become home to the largest common tern colony in western Europe. But in 2009 few young were raised at this colony.

In May of that year it became apparent that very few young had hatched. Bureau Waardenburg then carried out research into the breeding success of the terns; this was carried out on behalf of the Dutch BirdLife partner. This research revealed a shortage food for the chicks, which were starving en masse.

Although the chicks were being fed young smelt, perch and ruffe, these were too small and sufficient numbers of larger fish were lacking from the diet; it seemed that the adults just couldn't find enough of them. In spring 2009, commercial fishing for adult smelt was again permitted. There could be a possible relationship between this smelt fishing and the lack of suitably sized prey for the terns.

It was thought that the fishing for adult smelt would not cause a problem for the ecosystem as the young smelt serve as food for birds. Although earlier indications were that smelt form an important part of the diet for many birds species in the lake, there are now clear indications as to how important it actually is, particularly for the common tern. This research illustrates the importance of gathering up-to-date information, which can be used in the management of this Natura 2000 area.  

The consequences of this poor breeding success on the conservation objectives of the IJsselmeer are not yet clear. Besides the common tern, the lake is also used by black terns. The IJsslemeer serves as a major stopover site for almost the entire northwest European population of the black tern, which forage in the lake during their return migration to Africa.

This research was featured in the Dutch national newspaper the NRC in January 2010.

Contact person: