Some 170,000 people spotted 2,402,212 birds in their gardens at the weekend during this year’s national bird count.

Top of the list this year was the common sparrow, followed by the great tit and the blackbird.

Bird protection agency Vogelbescherming had asked people to be on the lookout for blackbirds in particular this year. In the Netherlands their number has dwindled by as much as 30%, figures by Sovon bird research have shown.

In 2018 the population was hit by the Usutu virus but that seems to have run its course, Ruud van Beusekom told broadcaster NOS. It is unclear what is causing its continuing decline. It is not the current bird flu epidemic, Van Beusekom said, because that virus does not affect songbirds.

‘The cause may be climate change and the dry summers of the last few years. Blackbirds eat worms and those can be found in moist soil,’ he said.