As many as 400 of the usually quite solitary birds travel to Anglesey to roost from far and wide. But why? Simon will be on the island trying to unravel the mysteries surrounding the raven.
View a slideshow of your amazing raven pictures in the Flickr group.
Watch all the best raven action from the shows.
A similar size to a buzzard, the legendary raven is the largest member of the crow family. With dark plumage and a brooding nature, it's certainly a majestic bird.
In flight look out for the diamond-shaped tail and watch the aerobatic display of stunts like looping the loop and flying upside down. Also listen out for its distinctive 'cronk cronk' calling.
Superstition and ill-omen have long surrounded the raven. Its reputation as a harbinger of death was earned in part by its carrion-eating but mostly by feasting on hanged corpses, inspiring Shelly to write "The obscene ravens, clamorous o'er the dead".
Once common throughout Britain the raven is now to be found in remote areas like moorland, mountains and rocky coasts nesting on a ledge or tree. Ravens pair for life and always return to the same nest which they build up every year.
You can help the BTO record bird movements and distribution throughout the UK online with BirdTrack.
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Simon King unravels the mystery of why ravens gather on Anglesey to roost.
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