The wigeon is a colourful duck that can often be spotted wheeling round our winter skies in large flocks. A dabbling duck, it surface-feeds on plants and seeds in shallow waters.

As its name suggests, Himalayan balsam is from the Himalayas and was introduced here in 1839. It now an invasive weed of riverbanks and ditches, where it prevents native species from growing.

Despite appearances, the slow worm is actually a legless lizard, not a worm or a snake! Look out for it basking in the sun on heathlands and grasslands, or even in the garden, where it favours…

A handsome gamebird, the pheasant is an introduced species that has settled here with little problem. It can be spotted in its farmland and woodland habitats, although you'll probably hear…

Heather is also called 'ling'. Look for it on our heaths, moors and bogs, where its delicate, loosely arranged pink flowers attract all kinds of nectar-loving insects.

The muntjac deer was introduced into the UK from China in the 20th century. It has gained a stronghold in southeast England, where it can cause damage to our woods through browsing.

As its name suggests, giant hogweed it a large umbellifer with distinctively ridged, hollow stems. An introduced species, it is an invasive weed of riverbanks, where it prevents native species…