Anga flew into Slimbridge at 0630 GMT on Saturday
The first Bewick swan has flown into the Wildfowl and Wetlands Trust (WWT) in Slimbridge from Russia more than a week later than expected.
Researchers at the Gloucestershire centre said the mild autumn and weeks of westerly winds had not provided the best conditions for the birds.
"Plummeting temperatures and easterly winds have encouraged the swans to complete their 3,000km migration."
The last time the swans were this late was in 1981.
Anga who has been visiting WWT Slimbridge since 2005 flew into the centre at 0630 GMT on Saturday.
"We were never in any doubt that the Bewicks would arrive at Slimbridge this year," Julia Newth said.
"But they are still a good week off the record for arriving late back in 1967, the first Bewick didn't arrive at Slimbridge until 9 November."
About 300 Bewicks are now expected to fly into the centre over the winter.