Native oysters are a staple of our seas and our plates - but our love of their taste has lead to a sharp decline all around the UK.

Frogbit looks like a mini water-lily as it floats on the surface of ponds, lakes and still waterways. It offers shelter to tadpoles, fish and dragonfly larve.

The variable damselfly looks a lot like the azure damselfly, but is much less common throughout most of the UK.

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.

The tiny, brown-and-white sand martin is a common summer visitor to the UK, nesting in colonies on rivers, lakes and flooded gravel pits. It returns to Africa in winter.

A tall and robust species of sedge, the Great fen-sedge has long leaves with sawtooth edges. It forms dense stands in lowland fens and around lakes.

The greenshank breeds on the boggy moors and ancient peatlands of Scotland. But it can be spotted elsewhere in the UK as it passes through on migration - look around lakes, marshes and the coast…

The attractive roe deer is native to the UK and widespread across woodland, farmland, grassland and heathland habitats. Look for its distinctive pale rump and short antlers.