An investigation has been launched after hundreds of birds fell from the sky ‘like rain’ outside a hospital.

The bizarre incident took place in Ferrol, north-west Spain and no one knows what caused the wildlife to descend from thin air.

Local media said that the starlings began hitting cars and pedestrians at around 9am on 26 November.

This happened outside of the Juan Cardona Hospital and police have since confirmed that no one was injured.

Mapi Rodríguez, president of the local resident association, told local media: “They came out of the trees in the emergency area of the hospital, flew a few metres and plummeted to the pavement.

“The birds have been collected and we are now waiting to find out what happened. We are told it won’t be easy.”

It is believed that two of the animals have been transferred by the regional environment agency for analysis and the Ferrol City Council has now joined in with the investigation.

Something like this could have been caused because of toxic chemicals in the sky which happened earlier this year when birds flew by a petrochemical plant in Tarragona.

But others have said it could be something to do with electrocution on a nearby powerline.

This hasn’t been confirmed but it is a well-known fact that Starlings fly in big, synchronised groups.

Earlier this year the same thing happened in Rome, Italy, with fears that New Year fireworks were to blame.

The animals were lying on the ground of the Italian capital’s Via Cavour, which is near the busy Termini train station.

While it was not confirmed what killed the birds – which were mainly starlings – animal rights groups said that the ‘massacre’ seemed to be related to a loud display of firecrackers and fireworks in the leafy neighbourhood that many birds use to nest.

The Italian branch of the International Organization for the Protection of Animals (OIPA) has called for a ban on selling firecrackers and fireworks for personal use, arguing they pose a threat to animals.

OIPA spokeswoman Loredana Diglio, said: “It can be that they died from fear. They can fly up together and knock against each other, or hit windows or electric power lines. Let’s not forget they can also die of heart attacks.”