This beautiful video shows a series of starling murmurations - one of the UK's most incredible wildlife spectacles.
Throughout autumn and winter, hundreds of thousands of starlings turn the sky black around the UK. The birds fly together in giant clouds, wheeling, turning and swooping in unison.
Why do they do it? According to the RSPB: "Starlings join forces for many reasons. Grouping together offers safety in numbers – predators such as peregrine falcons find it hard to target one bird amidst a hypnotising flock of thousands.
"Starlings also gather to keep warm at night and to exchange information, such as good feeding areas. They often feed miles away from where they roost - sometimes up to 20 miles away. They return to their roosting site at around the same time each evening."
Their timing is so precise that the RSPB's Johann Holt says: 'They are like clockwork – you know that at a certain time in the evening the sky will start to turn black, and it's mesmerizing watching the flock grow and grow.'
The RSPB says that the starling population has crashed by over 70 per cent in recent years, meaning they are now on the critical list of UK birds most at risk.
The decline is believed to be due to the loss of permanent pasture, increased use of farm chemicals and a shortage of food and nesting sites in many parts of the UK.
Endangered bird finds sanctuary in Northern Irish prison
Starlings make incredible shapes in Oxfordshire: Photos