Ring-necked parakeets are a common site in London's parks, but their origins had been a mystery until now. Some people believed this alien species, which originated in South Asia, was originally released into the streets of London by celebrities such as Jimi Hendrix and Katharine Hepburn.

These birds are one of the world's most successful alien species. In the UK, they have even been sighted on the northern coast of Scotland, in Northern Ireland, and on the Isle of Man.

One origin myth claims these wild birds first found a home in the UK when musician Jimi Hendrix released two parakeets on fashionable Carnaby Street in 1968. Another says that actress Katharine Hepburn may have accidentally released some parakeets while filming The African Queen. 

However, no one had attempted to debunk –  or prove – these widespread myths until researchers at Queen Mary University of London and Goldsmiths decided to look into them. 

They combined crime-tracking software and newspaper archives to determine if the birds were actually released in the famous locations. The five possible origin points were Shepperton Studios, Worton Hall Studios, Syon Park, Ealing Studios and Carnaby Street, all in or near London. 

The academics then looked at data collected by the NBN atlas, the UK's largest collection of biodiversity data, to analyze where in the city these birds have been spotted compared with where they were supposedly released.

They found no correlation between where the parakeets could have been released and where they were reported to have been seen. They also looked at thousands of articles published in the UK between 1804 and 2008 that referred to parakeets.

They were unable to find a single article referencing any of these famous stories. What they did find, however, were numerous accounts of diseases supposedly caused by parakeets published in the 19th century up until the mid-1950s. 

One article published in 1952 had a headline that said "stop imports of danger parrots." Sarah Elizabeth Cox, a postgraduate history student at Goldsmiths who did much of the archival work for this article, said: "It is easy to imagine [that headlines like this led] to a swift release of pets [by pet owners]."

She added: "If you were told you were at risk being near [a parakeet], it would be much easier to let it out the window than to destroy it." Cox said that by the 1960s, these birds were the UK's most popular pet, outnumbering cats and dogs.

Steven Le Comber, the article's head researcher, said: "The fun legends relating to the origins of the UK's parakeets are probably not going to go away any time soon.

"However, our research only found evidence to support the belief of most ornithologists: the spread of parakeets in the UK is likely a consequence of repeated releases and introductions, and nothing to do with publicity stunts by musicians or movie stars."