Living up to its name, the bullhead has a characteristically large, flattened head and a tapering body. Look out for it in fast-flowing, stony rivers and streams.

This striking black-and-white moth flies during the day in open woodlands, moorlands, and bogs. It's most common on Scottish moors.

The chocolate-brown, plump dipper can often be seen bobbing up and down on a stone in a fast-flowing river. It feeds on underwater insects by walking straight into, and under, the water.

A handsome fish, the tench has olive-green flanks, powerful fins and distinctive red eyes. It can be found in lowland lakes and slow-flowing rivers around the UK.

Water-cress has become so popular as a salad addition that it is now cultivated on a wide scale. In the wild, it grows in shallow, fast-flowing streams and is an indicator of clean water.

Known as the phantom of the forest, goshawks can fly through the trees at up to 40km per hour as they hunt birds and small mammals.