A summer visitor, the willow warbler can be seen in woodland, parks and gardens across the UK. It arrives here in April and leaves for southern Africa in September.

A well-travelled migrant, the painted lady arrives here every summer from Europe and Africa. This beautiful orange-and-black butterfly regularly visits gardens.

Although introduced by humans, the fallow deer has been here so long that it is considered naturalised. Look out for groups of white-spotted deer in woodland glades.

The pied flycatcher is a summer visitor, migrating here from West Africa to breed. Look for this small, black-and-white bird in woodland, parks and gardens, mostly in the west of the UK.

A plump gamebird, the red-legged partridge is an introduced species that seems to have settled here with little problem. It can be spotted in its favoured open scrub and farmland habitats.

In mild years, the spring-flowering primrose can appear as early as December. Look out for its pretty, creamy-yellow flowers in woodlands and grasslands.

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.

Only a few pairs of snow bunting breed here, so look out for this striking black-and-white bird in winter around Scotland, the North West and the East coast of England.

The pink-footed goose is a winter visitor to the UK, feeding on our wetland and farmland habitats. About 360,000 individuals spend the winter here, making it a really important destination for…

The black-and-white barnacle goose flies here for the 'warmer' winter from Greenland and Svalbard. This epic journey was once a mystery to people, who thought it hatched from the goose…