BLACKBIRDS spotted by pupils and teachers dropping from the sky and being unsteady on their feet outside a Cumbrian primary school were drunk, according to experts.

The birds, which regularly feast on fruit, were seen wobbling around and showing signs of sickness outside the un-named school.

Some of them survived the fermented berries but others were found dead — some from traumatic injury, possibly due to in-flight collisions caused by their intoxication.

Tests by Eden’s Animal Health and Veterinary Laboratories Agency revealed that all the birds had eaten rowan berries.

One of the birds had a high concentration of ethanol (pure alcohol) in its liver.

Tim Harrison, development officer at the British Trust for Ornithology's (BTO) Garden BirdWatch, said it was ‘very rare’ for birds to die in this way.

“Generally birds have a high tolerance to alcohol, especially the ones that regularly eat fruit,” he said.

“Waxwings eat a lot of fruit - their metabolism can handle the equivalent of an average size man drinking two and half pints of five per cent beer every hour of the day.”

He said blackbirds ate nearly as much fruit as the waxwing.

“It would probably take quite a large amount of spoiled fruit to create any problems for the birds,” said Mr Harrison.

“The alcohol levels in the berries eaten by these birds could have been quite high.”