A group of nature lovers were rambling through RSPB Otmoor near Marston last Saturday when the emerald-green herald flew up and alighted on an oak tree.
At first the bird watchers couldn't believe their eyes, but on closer inspection they realised the exotic-looking visitor was exactly what it appeared to be - an Australian budgerigar.
Fast-thinking Derek Latham, who had taken his camera along with him, managed to grab this exquisite shot of the bird just in time.
RSPB Otmoor volunteer Peter Barker said: "It flew in from the direction of Charlton on Otmoor, landed in an oak tree.
"Derek managed to take a picture of it then it flew back to Charlton on Otmoor.
"It was quite a surprise - that is not the sort of bird we were expecting to see.
"It could well be from the village, we just don't know. Sometimes these tropical birds do manage to survive in the wild. It's pretty cold at the moment but maybe it tucks in with a group of starlings at night."