Watch: Starlings swoop and loop in a breathtaking bird ballet

Welsh winter weather often involves descriptions of dark clouds forming over the fields, woodlands and reedbeds of Wales.

But these clouds filmed this week over Cardiff Bay are no ordinary clouds. They take your breath away!

Thousands of starlings come together at this time of year to provide one of the most breathtaking wildlife spectacles..

This congregation or murmuration was seen over the Cardiff Bay Wetlands Reserve

The reason for the extraordinary spectacle is not definitively known, with theories ranging from a defence mechanism against predators to attracting more birds to join their roost.

According to nature conservation charity the Royal Society for the Protection of Birds (RSPB), the starling population has crashed by over 70% in recent years. They are now on the critical list of UK birds most at risk.