This week, we are celebrating what must be the most committed visitors to an Oxford University museum.
They have travelled from Africa to visit the Museum of Natural History every year since 1948.
But although they stay from May to August, they don’t count towards the museum’s visitor numbers or leave any money in the donation box.
They are a colony of 60 pairs of swifts who settle in the ventilation shafts of the tower of the Museum of Natural History.
Keen birdwatcher Ronan Ferguson, 29, says: ‘Like the swifts, I make the journey to Oxford at around this time every year.
'It is a magnificent story that they have been coming here for so long, and there is no better setting to watch them from than from the Museum of Natural History.’
The swifts have been studied by the Edward Grey Institute of Ornithology since 1948.
Earlier this year, the Museum hosted the launch of the Oxford Swift City project, which aims to study swift populations in Oxford. Numbers of swifts in the UK have fallen by 47% since 1995.
The University is partnering with the City Council and the RSPB on this project.
You can keep an eye on the swifts via a live webcam.
Updates on when the chicks are hatched and how they are getting on are also posted on the Museum’s diary.