This small, white heron is an increasingly common sight in parts of the UK as it spreads north from continental Europe.

This slim fish is usually found on gravelly parts of the seabed, close to shore, but can turn up in rockpools.

The common octopus is a highly intelligent, active predator. It even has a secret weapon - special glands produce a venom that it uses to incapacitate its prey!

Red squirrels are native to the UK but are a lot rarer than their grey cousins. They live in a few special places across the UK thanks to reintroduction projects.

Ground-elder was likely introduced into the UK by the Romans and has since become naturalised. A medium-sized umbellifer, it is an invasive weed of shady places, gardens and roadsides.

This dainty white butterfly is now only found in a few parts of Britain, where it flutters slowly through woodland clearings.

As its name suggests, the scarlet elfcup is a bright red, cup-shaped fungus. It is widespread, but scarce, and can be found on fallen twigs and branches, in shady, damp places.