For reasons scientists don't yet understand, the population of Rose-ringed Parakeets in Britain has increased from 1,500 in 1995 to an estimated 30,000 in recent years.
The Rose-ringed Parakeet, native to the Indian subcontinent and sub-Saharan Africa, did not fly to London from those far-off places. Rather, it is widely assumed they either escaped from their British owners or were intentionally released.
What is confounding experts is the population explosion in these birds over the last decade. Where they were once considered exotic rarities, these days the parakeets are viewed as pests and a potential threat to crops.
Some of the theories as to why the birds are able to so rapidly proliferate include:
- The planting of exotic ornamental plants provides imported food to the parakeets.
- An increasing number of British residents have set up bird feeders and keep them filled with seed.
- A slightly warmer climate has caused the bird's metabolism to increase during breeding season.
- The warmer climate has increased the growth of a favorite food of the parakeets and/or has killed off a predator.
Researchers at Imperial College London are attempting to get a more accurate count of the current population of birds through Project Parakeet. According to The New York Times:
British officials are watching trends closely since the parakeets have proved major agricultural pests elsewhere, ravaging crops in places like India. So far, they have shown little predilection for leaving Europe's cities and suburbs for agricultural areas. (Far smaller flocks of rose-ringed parakeets have also arrived in other European cities like Brussels and Amsterdam.)