Lots of invasive species are now being tackled, hopefully these and grey squirrels will soon be a thing of the past.
Why are there parakeets in London?
A popular theory was that the birds escaped from the set of the 1951 film The African Queen, filmed in West London. Another rumour was that Jimi Hendrix released a pair on Carnaby Street, right in the centre of the capital. But according to a study which
mapped historical news reports of sightings of the birds, none of these urban myths are true.
The researchers from Queen Mary University of London wrote, 'most ornithologists believe the parakeets' spread in the UK is more likely to be a consequence of repeated releases and introductions'.
Scientists have worked out that most wild UK parakeets are descended from birds that originally came from Pakistan and northern India, which were kept as pets before being released © Rolf E Staerk/ Shutterstock
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But why would someone give up a precious pet? In the early 1930s and again in the 1950s, 'parrot fever' made headline news, the researchers found, with cases of bird owners catching psittacosis, a respiratory disease that can result in pneumonia and can jump from birds to people.
The Ministry of Health banned the import of birds for 20 years and scientists suspect pets may have been released by fearful owners or dodgy pet traders during this time.
Accidental escapes, such as when aviaries were destroyed by the Great Storm of 1987, could also have boosted wild populations - and not just in the South East.