Tens of thousands of starlings have flocked to a nature reserve in Carmarthenshire, performing spectacular aerial displays at dusk.
The Wildfowl and Wetlands Trust (WWT) believes 100,000 starlings have arrived at its Llanelli reserve in the last few weeks to roost for the winter.
It is thought the swirling, swooping displays are a way to avoid predators.
Although some of the starlings in the flock are native to the UK, many are from Russia and Scandinavia.
The WWT says it is by far the largest roost recorded at the 450 acre (182 hectare) reserve.
Dominic Carmichael, WWT's education manager at the wetland centre, said the arrival of the starlings was an "absolute joy".
"The idea of the flocking is fascinating. They tend to flock anyway because they are very sociable birds and being in a flock is a very safe thing to be. You're protected from being the one that's caught by the predator," said Mr Carmichael.
"The little flocks join together to create these huge roosts at night. Obviously there's an advantage in such large numbers. They feel safe, there's an element of body warmth.
"It's also perhaps a way of passing on information about where they can go and feed the next day because they are moving in from fields around," he added.
"The next day - woosh - they'll be off, going again, pecking away at the ground, picking up little leatherjackets and invertebrates from the soil."
Mr Carmichael said that despite the giant flock, or "murmuration", the population of starlings in the UK has been under pressure.
"There's been a big fall in breeding numbers over the last 50 years, a 70% decline," he said.
"The fascinating thing is how they don't all bump into each other. They are quite stunning. They have this amazing ability to turn very, very quickly.
"The basic rule is you don't bump into the bird next to you. You keep close, but you change when they change."
The WWT believes that careful land management at the reserve on the Burry Inlet has helped to attract the starlings in such large numbers.
Oliver Dodson, a WWT volunteer from Dafen, Llanelli, said creating the right habitat was critical.
"We think it's because of the way the reed beds are cut - it's good shelter for them. They like roosting in numbers for protection. It can support a vast number of starlings," he said.
The best time to see the starlings currently is from around 15:30 GMT, according to the WWT.