The bird - a Northern Mockingbird - was discovered in Pulborough.
Sighting of the bird, common in the USA, is only the fourth ever sighting in the UK.
Word of its presence soon spread and hundreds of keen birders swooped onto the RSPB reserve at Pulborough Brooks to try to get a glimpse of the visitor.
Bird lover and conservationist Matt Phelps managed to photograph the bird in the garden of his home in nearby Carpenters Meadow.
Matt, who was celebrating his 38th birthday, was delighted with his unexpected ‘present.’
“I have never seen one anywhere in the world, so to see one in my own garden was breathtaking,” he said.
“I still can’t believe it.”
He said mockingbirds - Mimus Polyglottos - were not usually migratory and it was possible that the bird had arrived in Britain on board a ship.
“But,” he added, “it’s not impossible that if crossed the Atlantic itself.”
Matt’s wife Kate and his parents Gill and Paul, who were visiting Matt for his birthday, were also delighted to see the bird.
It is thought to be the same bird which was spotted the previous day in Devon.