The female desert wheatear is thought to have become extremely dis- orientated while migrating to Africa and somehow ended up in freezing Aberdeenshire.
The bird – an old world flycatcher – is believed to be only one of a tiny handful of its kind ever to be spotted in Britain, but experts believe she can survive if she finds her way south to sunnier climes.
She was positively identified after staff at the RSPB reserve at Loch of Strathbeg, near Rattray, managed to photograph her earlier this week.
The bird is expected to remain at the reserve until the weather improves, before it will likely attempt to migrate again.
Diana Spencer, RSPB visitor officer at Loch of Strathbeg, said: "We've been excited to see a rarity here at Loch of Strathbeg – a desert wheatear spotted at Rattray.
"It should be in the Sahara by now so it's probably a bit stunned by being on a beach in Aberdeenshire in freezing temperatures.
"It was first spotted by two of our volunteers who were unsure what it was – but they brought in photos, which we then posted on Twitter. Within less than a minute we had two people identify the bird as a desert wheatear, which was excellent."
The bird is the same size as a robin and has distinctive black upper tail feathers. Experts believe it is female because of its grey colour, as males tend to be buff in colour.
Ian Francis, RSPB area manager for north-east Scotland, said: "There's every chance this lost bird will survive."