It’s called murmuration - the amazing sight of starlings swooping and swirling in huge flocks at dusk.
The phenomenon was captured by Star reader Glyn Wetherill in the skies above Stoney Middleton in these evocative photos.
Hundreds of thousands of birds can come together in huge clouds as the sun sets, wheeling, turning and swooping in unison.
But despite the impressive numbers seen here, starlings are still a species under pressure.
They used to be seen flocking over urban areas like Sheffield, but no longer - populations have crashed by 70 per cent in recent years.