27 May 2011
By Victoria Gill
Science reporter, BBC Nature
An increasingly ubiquitous visitor to English gardens, ring-necked parakeets divide opinion. For some, they are are exotic and colourful visitors. For others, a gaudy, noisy nuisance.
Now researchers say that they intimidate more familiar garden birds.
A team from Imperial College London has evidence that parakeets deter songbirds from using garden feeders.
The team says that reducing or managing the parakeet population "might be beneficial for song birds".
There are now an estimated 31,000 parakeets in the UK - mostly in and around London and south-east England. And the latest "parakeet census" shows that their numbers are increasing at an average of 23% per year.
Anecdotal evidence suggests that the UK's only naturalised parrot is becoming an agricultural pest, particularly for fruit-growers in the South East. But this study, led by PhD student Hannah Peck, is the first to apply a scientific method to find out what effect the parakeets have on garden birds.
She and her team looked specifically at feeding behaviour. They set up their experiment in 47 different gardens - putting a caged parakeet on a stand next to a garden feeder and filming the feeder to record what birds came to visit.
The scientists recorded the activity at the feeding station when the caged parakeet was present and when an empty cage was on the stand.
"We typically get blue tits and great tits on the feeders and so far the results have shown that they are more reluctant to feed when a parakeet is present," said Ms Peck.
"This is likely to be true for the other small birds too, such as coal tits, long tailed tits, greenfinches and goldfinches, but as we got such small numbers of these other species it will be difficult to tell from our data."
This is the first evidence for a negative impact of the parakeets' presence on native birds and Ms Peck will be presenting her findings at a British Ecological Society meeting on invasive species in June.
Garden parrotThe birds' native patch is in the Himalayas. But their adaptation to the cold - along with the plethora of lovingly topped-up peanut feeders in suburban gardens - appears to be helping them to thrive in the UK.
Ring-necked parakeets have also been introduced elsewhere in Europe. One recent study by researchers in Belgium investigated whether the parrots, which nest in tree cavities, were driving native nuthatches out of those same sites.
Although they found some competition for the nesting holes, the Belgian researchers concluded that parakeets would have a very limited impact on the country's nuthatch population.
The RSPB points out that there is, as yet, no published evidence to show that UK songbirds are affected by ring-necked parakeets.
Grahame Madge from the RSPB says that house sparrows and starlings are the only songbirds of conservation concern whose ranges overlap with the parakeets. And that they might simply be finding food elsewhere.
"Supplementary feeding for these species may be important," he told BBC Nature. "[But] we believe... insect-rich areas of grass and areas rich in seeds will provide the opportunities they need."
But the fact that they scare garden birds away from feeders is likely to enhance the parakeets' reputation as an invasive menace.
Ms Peck said: "We are not yet in a position to make a fair judgement on how best to manage the parakeet population but we hope that our research over the next couple of years will provide evidence for policy makers to do so."
Ironically, the fact that the population of parakeets is now so high means that it would be very difficult and very expensive to cull them, particularly as they live mainly in urban and suburban areas.
"In the long term, other birds might just get used to the parakeets," said Ms Peck.
Mr Madge concluded: "It is important that the spread of the ring-necked parakeet is monitored, and that studies like this one continue to investigate the potential impacts on our native wildlife."
A full report about the decline in British songbirds will feature on Countryfile on Sunday 29 May, 1900BST, BBC Onehttp://www.bbc.co.uk/nature/13524396
