On 17 and 18 December 2021, a few hundred dead knots (Calidris canutus) were discovered on Schiermonnikoog and in Oost-Groningen . At the behest of the Netherlands Food and Consumer Product Safety Authority, Wageningen Bioveterinary Research (WBVR) examined a few dead knots, an oystercatcher, and a curlew who were found in the same location. The H5N1 virus was detected in the birds examined. It is suspected to be the highly pathogenic variant, but this is under further investigation.
Most of the dead birds were found along the shoreline. The knots most likely died above the sea, and some of them washed ashore. The Wadden Sea is an important resting area for wild birds in the Netherlands. Knots also winter in the Netherlands, on mud flats of tidal areas, sometimes in enormous groups.
It is not the first time that large groups of dead wild birds with avian influenza have been found in the Wadden Sea. At the end of April 2021, hundreds of dead wild geese, barnacle geese in particular, were found along the coast of Friesland and Groningen. HPAI H5N1 viruses as well as some HPAI H5 viruses of which the N-type could not be determined were detected in the barnacle geese examined.
