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.

The mountain hare lives in the Scottish Highlands and the north of England. They are renowned for turning white in winter to match their upland surroundings.

This striking duck was introduced to the UK and is now established as a breeding bird in England.

The common sandpiper breeds along rivers, and by lakes, reservoirs and lochs in upland Scotland, Northern England and Wales. It can be spotted as a passage migrant at many inland wetlands across…

The thick topshell is a common sight on rocky shores in Wales and South West England.

Egyptian geese were introduced to Britain from Africa. They are now widespread in southern England.

You are most likely to spot the cat flea if you have pets. It will feed on cats, dogs and people, although it can't live on us. It is a pest and needs to be controlled in the house for the…

The willow tit lives in wet woodland and willow carr in England, Wales and southern Scotland. It is very similar to the marsh tit, but has a distinctive pale panel on its wings.

As the name suggests, this beautiful brown butterfly is most common in Scotland, though it can also be seen in northern England.

Considered Britain's most threatened butterfly, the high brown fritillary can be only be found in a few areas of England and Wales.