Common alder can be found along riversides, and in fens and wet woodlands. Its exposed roots provide shelter for fish, and its rounded leaves are food for aquatic insects.

The fearsome common backswimmer hunts insects, tadpoles and fish. It uses its oar-like legs to swim upside-down under the water's surface where unsuspecting prey can be found.

So-named because its gnarled trunk can split as it grows, the crack willow can be seen along riverbanks, around lakes and in wet woodlands. Like other willows, it produces catkins in spring.

Look for the star-like, feathery, white flowers of Bogbean in ponds, fens, bogs and marshes. It is so-named because its leaves look like those of broad beans.

Despite its warts and ancient associations with witches, the common toad is a gardener's friend, sucking up slugs and snails. It is famous for migrating en masse to its breeding ponds.

The gudgeon is a bottom-dwelling fish, similar to the stone loach, but with only two whisker-like barbels near its mouth. These sensory organs help it to find its prey in the sand and gravel of…

A member of the buttercup family, Common water-crowfoot displays white, buttercup-like flowers with yellow centres. It can form mats in ponds, ditches and streams during spring and summer.

Flowering rush is a pretty rush-like plant of shallow wetland habitats, such as ponds, canals and ditches. Its cup-shaped, pink flowers appear in summer, brightening up the water's edge.

A fierce pirate of the sea, the Arctic skua is renowned for stealing fish from other seabirds and dive-bombing anyone that comes near its nests. It breeds in the far north of Scotland and on the…

A large hawker, the common hawker can be seen throughout the summer and into autumn. A fast-flying insect, it catches its prey mid-air. Look for it around ponds in the uplands of the north and…