Non-native songbird 'could change Britain's dawn chorus'

A tiny but loud and brightly coloured songbird from subtropical Asia could be emerging as a new invasive species in Britain, threatening to dominate the dawn chorus of native European Robins, Blackbirds and warblers.

A new study led by UK Centre for Ecology & Hydrology (UKCEH) warns that Red-billed Leiothrix could become as familiar in gardens, parks and woodland as Ring-necked Parakeets, whose numbers have rapidly increased since becoming established in this country in the 1970s.

Red-billed Leiothrix has already become established in several parts of Europe, and the new study documents new sightings in Britain, including a cluster in Wiltshire and Somerset, suggesting the species could soon become established in the wild. Like parakeets, they are kept as cagebirds but have either escaped or been released into the wild.

This charismatic and beautiful bird has a bright red bill, a yellow-orange throat and an olive green head and grey back, and its melodious song is comparable to the native Blackcap, Blackbird and European Robin.

Sightings of Red-billed Leiothrix are on the up in Britain. This one was in Somerset in February 2019 (Mike Trew).

Dr Richard Broughton, a UKCEH ecologist who led the study, which has been published in the journal Ibis, explained: "If Red-billed Leiothrix becomes established in Britain, they could soon be a familiar sight in our gardens, parks and woodland, with their rich song altering the dawn chorus as we know it today.

"Our study is the very first assessment of this species in Britain, and raises awareness of the fact that the birds have been sighted in Britain. The potential for the Red-billed Leiothrix to become established here had seemed very low, but the cluster of records in southern England suggest we need to take it seriously as a potentially new invasive species."

Milder winters as a result of climate change will make it easier for Red-billed Leiothrix to become established and spread in Britain, while the prevalence of birdfeeders in Britain's gardens would give it a reliable food source to tide it through any bad winters and weather.

Red-billed Leiothrix is native to southern China and the Himalaya. When it has established elsewhere, it has become an abundant and dominant member of the wild bird community. In Europe, populations are well established in Italy, France, Spain and Portugal, while further afield it has also become numerous in Japan and Hawaii.

Ecologists are concerned they may compete with native birds, such as European Robins, for habitat, living space and food, potentially harming their populations. However, the new study makes clear that more research is needed to establish the longer-term effects of their introduction.

Dr Broughton says that monitoring of the Red-billed Leiothrix in Britain will be crucial in determining its prevalence in this country, and asked the public to report sightings via the British Trust for Ornithology's BirdTrack app or the iRecord app. There is information about invasive species and how to report them on the Great Britain Non-native Species Secretariat website.

Reference

Broughton, R K, Ramellini, S, Maziarz, M, & Pereira, P F. 2022 The Red-billed Leiothrix Leiothrix lutea: a new invasive species for Britain? Ibis. DOI: 10.1111/ibi.13090.