Birdwatchers have chartered four planes to fly to Orkney to spot a blackbird which has never been seen before in the UK.
The red-winged blackbird is an American species which was spotted by a local bird observatory on the island of North Ronaldsay on Saturday.
Now scores of twitchers have taken advantage of the Bank Holiday weekend and chartered planes to go and see the rare bird, which was spotted by Simon Davies, principal assistant warden of the North Ronaldsay Bird Observatory.
Mr Davies was doing a bird census when the blackbird "popped up its head behind some gas cannisters", said Larissa Simulik, an assistant warden at the observatory.
WTF! We think we know what this is but we still don't know 100% but it's good... pic.twitter.com/DDZluh7xQn— North Ron Bird Obs (@NRonBirdObs) April 29, 2017
She added: "He could not believe his eyes and nor could I when I saw the photographs. There was a bit of detective work to identify it but it is a female red-winged blackbird.
"There have been recent strong westerlies and other pressures in the atmosphere that could have helped it across the Atlantic, or it simply could have landed on a boat and then hopped off.
"It is near a marshy area which it likes and there is no way of telling how long it could be here - it may a short time or a long time. We have four charter planes coming in - it is going to be very busy."
The red-winged blackbird is normally found in most of North and much of Central America.
It breeds from Alaska and Newfoundland south to Florida, the Gulf of Mexico, Mexico, and Guatemala, with isolated populations in western El Salvador, northwestern Honduras, and northwestern Costa Rica.
It may winter as far north as Pennsylvania and British Columbia, but northern populations are generally migratory, moving south to Mexico and the southern United States.
Claims have been made that it is the most abundant living land bird in North America, as bird-counting censuses of wintering red-winged blackbirds sometimes show that loose flocks can number in an excess of a million birds per flock and the full number of breeding pairs across North and Central America may exceed 250 million in peak years.
It also ranks among the best-studied wild bird species in the world. Seeds and insects make up the bulk of the red-winged blackbird's diet.
Josh Jones, of the authoritative Birdguides, said that it was a good sign that the red-winged Blackbird found on Orkney had survived into a second day on North Ronaldsay.
"There is no telling how long it could stick around, these things tend to be short lived once they are found - so that's why people are travelling from all over the country to get to see it while they can.
"They are coming from London and elsewhere throughout the UK. Many, many birders will seize the opportunity over the bank holiday," he said.
"It really is a momentous find. I suppose the surprise is that it has not been recorded in the UK before because the Northern population in the USA does migrate over long distances. It can travel far.
"Who knows how this bird made it here? It is possible it was the right atmospheric conditions or that it came at least part of the way on a boat.
"It is also possible that it actually arrived in autumn's storms - when a lot of American migrants came - but has only been seen now. We will never know - it's just speculation.
"But the important thing is that it is here. It is quite incredible to think that this bird is so widespread across America but has only now been discovered here."