An Egyptian vulture seen on the Isles of Scilly was described on Monday as the "bird of the century" after it was sighted in Britain for the first time since 1868.

Birdwatchers flocked to the islands, off the Cornish coast, after the endangered bird of prey landed on a peninsula – only the third time one has been sighted in the UK.

It was photographed flying over Peninnis Head on St Mary’s on Monday morning before later being seen on Tresco, where it perched in a pine in the middle of the day.

The vulture is believed to have been blown off course from its home, most probably in Spain but possibly further afield, by recent unseasonal weather patterns from the south.

Only two official sightings have been recorded in the UK – in Somerset in 1825 and Essex in 1868, and those were only positively identified after being photographed.

The sighting prompted Rare Bird Alert UK, which flashes news of any rare sighting to its 68,000 followers, to describe the sighting as a "Mega Alert".

One bird-watcher said: "This is the biggest sighting of the century in some respects as the last one was in Essex in 1868 and the only other one in 1825. Both were shot!

"To see it this far off course now is something that will get birdwatchers flocking to Cornwall if they can avoid the G7 security."

Also known as "the pharoah’s chicken" because of its links to ancient Egypt, the bird is among the very few to use tools, such as adopting a pebble as a hammer, to break the eggs of other birds in order to eat the contents. It also eats carrion, rodents and reptiles.

The sighting marks a remarkable month for British birders so far, having already included the first ever UK sighting of a sulphur-bellied warbler as well as very rare species such as the calandra lark, collared pratincole and red-necked stint.