Aidan Williams says he has been dive-bombed by the predator on a regular basis on a country lane near his home in Sandon, Staffordshire.
See also: Baby owl clings to birdbox for dear life
Experts believe the bird – which Mr Williams thinks could be a hawk – is resorting to the aggressive behaviour because it's trying to protect its young.
But bizarrely, the bird only seems to target him and ignores other cyclists, cars and walkers.
The bird specifically targets Aidan and it's not clear why
Experts believe it is protecting its young
Speaking to the BBC, environment correspondent David Gregory-Kumar said: "It's the right time of year for that [protecting young] to happen.
"But singling out one person is stranger behaviour."
He added the creature may actually be a sparrow hawk or a merlin.
The UK has numerous different types of birds of prey.
The largest is the White-tailed eagle, which are on the red list for endangered species and found in northern Scotland.