Been going through some old videos and found this one from a few years ago, filmed in Regents Park, London. What has happened here is a magpie (a species that is a known egg thief) has got too close to a mistle thrush nest and the parents are not happy! Watch what happens when the magpie gets on top of the first mistle thrush – the second one does not hold back!
Magpie vs mistle thrushes from Neil Phillips on Vimeo.
This all happened on one of the busy paths in this urban park, you can hear footsteps of passing people and sirens and traffic from the nearby road!