The Sitka spruce was introduced into the UK from North America in the 19th century. It has been widely planted as a forestry tree; look for classic needle-like leaves and pale brown, domed cones…

Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from…

These non-native limpets arrived from America in the 19th century and are now widespread in the UK. They form stacks and have a specially adapted shell which, when flipped upside down, looks like…

Introduced into the UK in the 19th century, the diminutive little owl can now be seen along hedgerows, on farmland and in parkland across England and Wales. It often perches on a pole or rock,…

This large shrike visits the UK in small numbers each year, passing through on migration or spending the winter here.

The ocean sunfish is the second largest bony fish on the planet and visits UK seas during the summer months to feast on jellyfish.

An attractive, olive-green bird, the greenfinch regularly visits birdtables and feeders in gardens. Look for a bright flash of yellow on its wings as it flies.