This is the ghostly imprint of a tawny owl which has left its mark after swooping straight into the window of a Norwich woman's flat.

Sally Nairn, 38, who lives in Catton Grove Road, was sitting in the living room of her first floor flat talking to her friend, Rachel Elliott, who pointed out the image, complete with the impression of eyes, a beak and open wings on the window.

Miss Nairn said: 'Rachel thought something had hit my window and we could see the image of an owl. The week before I had heard an owl hooting outside and I thought it was strange because we don't normally get owls where I live.

'I never heard the owl hit the window.

'The sun was streaming through the window and we could see the image.

'I have never seen anything like it before in my life and I had never heard of the dusting on the window. It's a ghostly image. It was still there this morning but I don't know how long it will last. It must have happened over the weekend.'

Erica Howe, communications officer for the Royal Society for the Protection of Birds, said she thought it was a tawny owl.

She said: 'Normally we would be able to tell if it is a tawny owl or a barn owl because of its size but the imprint is distorted because of the collision. Chances are if the owl has not been found directly below the window then it flew away.

'It looks like the owl took a hit so unless it has been found it will be fine.

'They are fairly hardy creatures.

'The residue is powder down which is a really soft feather that a lot of birds have when they are really young and owls have them through their whole lives.'