Fishermen have reported seeing hundreds of common migratory birds plunging to the deaths in the past week.
“While fishing about 10 miles south of Portsmouth in England, we witnessed thousands of garden birds disorientated, land on the sea and most drowning,” one boat skipper told Britain’s Royal Society for the Protection of Birds (RSPB).
“Species included goldcrests, robins, thrushes and blackbirds. The sky was thick with garden birds. I estimate I saw 500 birds die and that was just in our 300-yard sphere.
“On the way home we just saw dead songbirds in the water: it was a harrowing sight.”
RSPB conservation director Martin Harper said the scale of the deaths was shocking and could affect the survival of the bird species.
Experts believe the birds fell victim to a combination of fog and heavy winds as they travelled across the north sea from Scandinavia.