The Migrant hawker is not a particularly aggressive species, and may be seen feeding in large groups. It flies late into autumn and can be seen in gardens, grasslands and woodlands.

Pineappleweed is an introduced species that has become a widespread 'weed' of disturbed ground, such as pavements and roadsides and gardens. It has feathery leaves and yellow flower…

Escaped or intentionally freed from fur farms in the 1960s, the American mink is now well established in the UK. Its carnivorous nature is a threat to our native water vole and seabird populations…

One of the most eye-catching sights on the rocky shore, this mind-boggling species resembling a collection of beautiful pressed flowers is actually a colony of individual animals!

The turtle dove is the UK's fastest declining bird species and is on the brink of extinction. A small and pretty pigeon, it breeds in lowland England and winters in Sub-Saharan Africa.

A tall and robust species of sedge, the Great fen-sedge has long leaves with sawtooth edges. It forms dense stands in lowland fens and around lakes.

One of the most colourful fish in UK seas, the cuckoo wrasse looks like it belongs in the tropics. Don't be fooled though, it's very much a native species.

The White-clawed crayfish is a freshwater, bronze-coloured crustacean with pale undersides to its claws - hence the name. It is under threat from an invasive and introduced species of crayfish.…

Buddleia is a familiar shrub, well-known for its attractiveness to butterflies. It is actually an introduced species, however, that has become naturalised on waste ground, railway cuttings and in…