Parakeets are Britain’s most successful invasive bird species, but they are not the only one. Birds such as the common pheasant, native to Asia, and the Canada goose, have been established in Britain for centuries. The red-crested pochard duck, with its orange-brown head and red beak, can sometimes be spotted on Britain’s waterways, as can black swans. Few of these birds, though, are thriving: the golden pheasant (smaller than its common counterpart, with a yellow crown, red belly and fine tail) is just about hanging on.
One invader, however, seems to be on the rise: the red-billed leiothrix. Native to Southeast Asia and the Himalayas, this 15cm songbird, olive green with a bright red beak and yellow throat, was popular as a pet in the UK until 2005, when imports…