Autumn bird migration is in progress, stay alert for Avian Influenza
Even though reports indicate that highly pathogenic avian influenza (HPAI) is still circulating in wild birds in the Netherlands, this has not led to an increase in wild bird mortality in over 6 months. However, with the autumn migration of birds new variants of the virus might be introduced that can change the situation in the Netherlands. Naturally, we hope that this will not happen and closely observe the situation.
Reports
The Dutch Wildlife Health Centre and Sovon have received 145 reports of dead waterbirds from June to September 2024 compared to 1619 reports during the same period in 2023 and 897 in 2022. Therefore, this quarter remains quiet, just as the previous one.
Results
During the first nine months of the year, Wageningen Bioveterinary Research (WBVR) has received 273 dead birds which were reported to the DWHC and Sovon. In 5% of these animals, HPAI was detected. These positive cases were detected in five Barnacle geese, two greylag geese, two lesser black-backed gulls, one giant Canadian goose, one greater white-fronted goose, one mallard, one black-headed gull, one great black-headed gull and one carrion crow. In the previous years, the proportion of positive tested animals was much higher, with 389 out of 971(40%) positives in 2023, 500 out of 1072 (47%) positives in 2022 and 230 out of 782 (29%) positives in 2021. More details on those numbers can be found on the website of the DWHC: https://dwhc.nl/laatste-informatie-testresultaten-vogelgriep.
Situation in neighbouring countries
In previous years outbreaks of avian influenza were occurring in (late) autumn. Thus, we have to be aware that new variants of the virus might be introduced to the Netherlands via migratory birds this year. To better estimate this risk the Bird Flu Radar is continuously being improved (https://www.sovon.nl/actueel/nieuwsberichten/update-van-de-bird-flu-radar-helpt-risico-op-uitbraak-vogelgriep-nog-beter) and being cautious when out in the field is still important.
Monitoring of dead birds
The project LiveAtlas from Sovon aims to better visualize mortality patterns of dead birds on maps and now also allows for the inclusion of dead birds without indication of HPAI presence. From now on, the LiveAtlas project allows bird watchers to keep a list of all observed bird species – dead or alive- and their numbers during excursions. We hope that we can get a better overview of mortality patterns and obtain more quantitative data about increases in mortality and background mortality (https://sovon.nl/tellen/telprojecten/liveatlas).
Keep reporting
We would like to thank everybody who went through the additional effort of reporting or submitting dead birds. Naturally, we are inviting you to keep reporting in the upcoming months. This way, we can have a good overview of what is happening in nature. Some dead birds may be interesting for research and can be submitted to us. If you would like to discuss this possibility, we advise you to contact the DWHC under the following phone number: (030-2537925).
Roy Slaterus, Sovon Vogelonderzoek Nederland
Valentina Caliendo, Dutch Wildlife Health Centre
