Experts believe the buzzard - which can weigh up to 1kg and have a wingspan of a metre - may be protecting a nest.

In one vicious attack the bird struck a woman on the head as she was pedalling down a road on her bike close to the town of Holsworthy in Devon.

Emma Parkin, from the Royal Society for the Protection of Birds, said that painting large eye shapes on cycling helmets could help scare the bird off.

"They are normally very timid, but this one appears to have lost its fear of man and clearly must have a nest close by which it is protecting," said Ms Parkin.

Frightened

Local cycling club member Linda Johnston was a victim of the buzzard and said the attack was terrifying.

"After it hit me I could see it hovering and thought it was going to come back, so I speeded up and got away as quick as I could.

"It really did hurt and gave me a fright," she added.