The herring guinea fowl was ringed as a youngster in 1973 on Stora Karlsö on Gotland.
It was found in April on a beach on the south coast of Skåne between Trelleborg and Höllviken and is believed to have been dead for a few months and now researchers at the Swedish Museum of Natural History are waiting to get the bird in.
- It was in the air that it would be a herring guinea pig that broke the old record, says Thord Fransson, researcher at the Swedish Museum of Natural History.
Third oldest in Europe
The previous record was also held by a herring guinea fowl from Stora Karlsö.
It was 47 years and 10 months.
And the researchers know of about 10 herring guinea pigs that have reached the age of over 40 years.
The bird is the third oldest from the ringing in Europe.
The oldest ringed bird in the world is a laysanal albatross that was at least 70 years old when last year it was observed alive with its young on the Midway Atoll near Hawaii.
Listen to the video about why herring guinea pigs are getting so old and about the 70-year-old albatross.
Of birds that have not been possible to ring in the same amount - which tips do you think can be the oldest?
One candidate is the relative Tordmule, who may probably be in the vicinity of the herring guinea pig in age.
Our records are just over 30 years old, but there is a European thunderstorm that has turned 45 years old.