As tropical birds go, few look more like they belong in the jungle than the monk parakeet. It is noisy, and has iridescent green and blue plumage and an orange beak that looks like an offensive weapon. But, for all its exotic appearance, it has somehow found a way to settle down in the Home Counties.
It is the latest tropical bird to raise young in Britain, following the success of the ring-necked parakeet which now throngs south and west London. The South American bird, which can live as long as 30 years, has founded colonies in Wiltshire, Hertfordshire and London, and also been spotted in Cheshire and Devon.
But its place on our list of resident birds could be short-lived. The bird may be colourful, a good talker and popular as a pet, but when it goes into the wild, it can cause problems.
Despite being similar in appearance and behaviour to the UK's 4,300 ring-necked parakeets – both species are often spotted in parks and gardens eating out of bird feeders – it is monk parakeets' unusual nesting habits that make them the bigger threat. Unlike other parrots, they use sticks to build huge colony nests on the outside of trees or pylons that can reach the size of a small car. In the US, monk parakeets are reported to have caused costly and dangerous power shortages, fires, problems with electricity transmission and crop damage. In some states, ownership, let alone release, of the species has been banned.
No serious damage has so far been reported in the UK, but the birds' numbers – currently estimated to be about 100-150 – are expected to rise dramatically, given the ease with which they can survive in cities and a range of climates. So no sooner do bird lovers hear of the new addition to the country's fauna than they will be learning of its looming demise. Inquiries by The Independent on Sunday have revealed secret plans by the Department for Environment, Food and Rural Affairs (Defra) to exterminate the bird, bringing to an end its short-lived residence in Britain.
Defra's culling policy was decided in December 2010, but Defra has yet to make it known to the public. A spokesperson said: "This invasive species has caused significant damage in other countries through nesting and feeding activity, and we are taking action now to prevent this happening in the UK."
The Royal Society for the Protection of Birds (RSPB) supports Defra's move. A spokesperson said: "These species aren't causing any major conservation problems in the UK at the moment, but they might in future."
According to Defra, the cull – which will involve shooting, trapping and nest removal – will be a lot cheaper and easier now than it would if the population were allowed to grow.
Not everyone is happy about the decision. A risk assessment of the species conducted by the organisation GB Non-Native Species Secretariat says the threat it poses is relatively minor, and that farmers have overstated the problems the birds cause. Kate Fowler, campaigns co-ordinator for Animal Aid, said: "This document accepts that there will be public opposition – so no wonder they have kept it quiet. If Defra wants to see an end to non-native species living in the UK, it should ban the importation and breeding of them for the pet trade. In the meantime, if it regards them as a problem, it should investigate non-lethal measures instead of rushing to kill."
These highly intelligent and sociable birds are sold across the country in pet shops and are chosen for their ability to develop large vocabularies. Although it is against the law to release parakeets, people continue to do so. And the birds are already resident in Belgium, Spain and Italy, so even if England's population were destroyed, the birds could well return.
Defra argues that non-native species cost the British economy £1.7bn every year. This figure is based on a Defra-sponsored report called The Economic Cost of Invasive Non-Native Species to Great Britain. However, according the report, the total cost of parakeets in Britain is only £10,000 each year – so far.
Defra refused to confirm if the culling process has begun.
They come over 'ere... Other visitors that have outstayed their welcome
Grey squirrel (Sciurus carolinensis)
Notorious usurpers of the smaller, native red squirrel, greys were introduced from the US at the start of the 20th century and have squeezed red squirrels out of most of the UK. According to the Forestry Commission, there are currently 2.5 million grey squirrels, compared with a native red population of only 140,000.
Red-eared terrapin (Trachemys scripta elegans)
These antisocial reptiles were rounded up and deported from London six years ago after terrorising ducks in a local park. They are exported from the US and bought as pets, and often released into the wild by irresponsible owners. It is thought that rising temperatures could increase their breeding potential in Britain.
American mink (Neovison vison)
Originally bred for their fur, large numbers of these voracious carnivores escaped and have now firmly established themselves in the UK. They are a major threat to native populations of water fowl, ground-nesting birds, small mammals and fish, all of which are lunch for a mink. They have been subject to culling in Scotland.
Muntjac deer (Muntiacus reevesi)
Introduced from south-east Asia as ornamental deer for aristocratic gardens, these irrepressible breeders quickly spread into the British countryside and woodland. They are now becoming more common in towns and cities. It has been claimed that they damage woodland areas by eating saplings.
Eagle owl (Bubo bubo)
A small number of these powerful predators, native in most of the Eurasian landmass, are known to breed in Britain. It is believed that the British breeding pairs were released or escaped from captive collections. Farmers fear they pose a threat to livestock.
Chinese mitten crab (Eriocheir sinensis)
First recorded in the River Thames in 1935, these troublesome freshwater crustaceans arrived in Britain in trade ships. Now firmly established along many of Britain's rivers, their burrowed homes weaken the structural integrity of riverbanks, threatening other semi-aquatic species.