Rare visitors to the Wildfowl and Wetlands Trust (WWT) at Slimbridge, Gloucestershire have attracted more than 1,000 twitchers since last Friday.
It is hope the birds will stay and breed at Slimbridge
The arrival of the flock of 17 Glossy Ibis, a medium-sized, heron-like bird, shocked bird watchers and staff.
A WWT spokesman said it was surprised when the flock flew in but even more so that the birds were still on site.
"It would be great if they stayed and created the first breeding record for the species in the UK," he said.
The ibis' which boast long curved bills and beautiful, iridescent bottle-green and red plumage are usually found in southern Europe.
The birds spend the winter in Africa before migrating north to Southern Spain and Greece for the summer.
It is believed a south easterly wind on Friday encouraged the birds to fly to the UK.
It is thought the flock of 17 birds is the second largest ever to arrive in the UK.
The previous largest flock was more than 100 years ago when 20 ibis showed up in the Shetland Islands.