Vogelgriepvirus type H5N1 zorgt voor sterfte onder Nederlandse Haviken Accipiter gentilis

In a mixed woodland in the northern Netherlands (Lheederzand, mostly coniferous but mixed with deciduous trees, sandy soil, surrounded by farmland, villages and campings, and a large nature reserve with many fens) an adult male Goshawk was recorded on 12 April 2022 within 60 m of its nest, landing in a Scots Pine Pinus sylvestris. The bird could be approached on foot to within a few meters, without the Goshawk showing any sign of distress. Eyes were held closed, even when two people were talking, standing and walking beneath the sitting post. Sudden harsh sounds caused the bird to shortly open its eyes (which then showed enlarged pupils), but still without any intention to flee. The next day it was found on the ground under the same tree, still alive but without fighting spirit. The head was slightly twisted, and the pupils were unnaturally enlarged and contracted rapidly and erratically (on film: 50 times in 25 seconds). It died the next day. The breeding site remained deserted throughout the summer (no sign of the female). Analysis by Dutch Wildlife Health Centre (DWHC) proved that the bird was infected with H5N1 avian influenza virus. A similar incidence was recorded for an adult male Goshawk near Sassenheim in the western Netherlands (peaty soil, below sea-level, park amidst a village, lakes and polders within flying distance). This bird was spotted on 23 August 2022, the observer alerted to its presence by way of alarm-calling Jays and Magpies. The Goshawk sat on a branch, immobile and silent with slightly drooping head, eyes closed and without any reaction to corvids nor observer. It was found dead under the tree on 25 August. Analysis by DWHC proved again that it was infected with the H5N1 virus. Despite the divergent habitats that these two birds occupied (sandy soil versus peaty soil, thinly versus densely populated) the finding sites had in common that within a few km both were surrounded by farmland (arable and dairy) and wetlands abounding with waterbirds (geese, ducks) throughout the year. The summer diet of the Goshawk pair at Lheederzand, based on prey remains collected in 2009-22 near/on the nest (n=50), showed a concomitant diversity, ranging from waterbirds (Anas crecca, Chroicocephalus ridibundus) to small raptors, waders, doves, woodpeckers, owls, thrushes, Starlings Sturnus vulgaris, corvids and Rabbit Oryctolagus cuniculus. Goshawks lead a solitary, territorial and resident life, but are generalist predators that cover a wide range of prey species from a large variety of habitats, including wetlands where the chances of contacting the avian influenza virus are better than average.