Intruder driven off Norwich Cathedral peregrine nest
9 April 2014 Last updated at 15:34 BST
A rogue bird which invaded a peregrine falcon nest where four eggs are being nurtured, apparently threatening to destroy them, has been caught on camera.
A female peregrine flushed the father from the nest on the spire of Norwich Cathedral and then indicated it was "toying with the idea of breaking them," according to the Hawk and Owl Trust.
The invader eventually flew off, leaving the eggs undamaged, when the adult male made "high speed low passes over her head".