ORNITHOLOGISTS are asking people if they have ever seen a black swan here in Britain as they draw up an atlas of non-native bird species that have settled here.

Scientists from the British Trust for Ornithology (BTO) backed by the environment department Defra want to establish if once imported species like the black swan – brought in from Australia – can now be considered native.

Some of the “imports” are decidedly exotic but seem to be happy here: there are reported to be more parakeets in some areas of the South East than some native species like the house sparrow, whose numbers are in steep decline for reasons not fully understood.

But colourful as they may be, the “foreigners” could also be a threat to native species.

Dawn Balmer, who is organising the latest BTO bird atlas, commented: “We receive a lot of information from our volunteers about our native birds but we get very little about escaped ones.

“Collecting this information is important as non-native species can pose a serious threat to our natural biodiversity. So if you see a Black Swan or any other exotic birds please let us know.”

Records can be submitted as part of the mapping project at www.birdatlas.net