To track all members of alien animal species in the United Kingdom.

Note that this project defines 'alien' as being 'neither native nor having a significant established introduced population'. The purpose of this project is to collect rare sightings of unusual species, rather than the relatively common introduced species such as the Eastern Grey Squirrel or Feral Pidgeon.

See the 'Introduced Animal Species in the United Kingdom' collection project below for examples of what not to include. Members of species on this list with a small number of sightings may still be appropriate - use your discretion, but around 50 sightings or less is a good level for a cut-off. Escaped or feral species with a significant level of domestication, such as the Domestic Horse, will generally not be appropriate.

https://www.inaturalist.org/projects/introduced-animal-species-in-the-united-kingdom?tab=species less ↑