The large, dark grey water shrew lives mostly in wetland habitats. It's a good swimmer that hunts for aquatic insects and burrows into the banks.

The common spangle gall wasp produces a small, disc-shaped growth, or 'gall', on the undersides of oak leaves. Inside the gall, the larvae of the wasp feed on the host tissues, but cause…

The knopper gall wasp produces knobbly red, turning to brown, growths, or 'galls', on the acorns of Pedunculate Oak. Inside the gall, the larvae of the wasp feed on the host tissues, but…

The common walnut tree produces a large, brown nut that is familiar to so many of us. It is an introduced species in the UK, found in towns, gardens and parks.

The silvery dace can be seen gathering in large shoals in lowland rivers and streams. It is a member of the carp family and looks very similar to the chub, but is smaller.

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 marsh hair moss is the largest moss in the UK. Look out for it in damp woodland and on boggy heathlands where it forms large, green and spikey 'cushions'.

The migrant hawker is not a particularly aggressive species, and may be seen feeding in large groups. It flies late into autumn and can be seen in gardens, grasslands and woodlands.

As its name suggests, Water dock likes damp places, such as the egdes of canals, ponds and rivers. It is a tall plant with large, greenish flower spikes.

The alder fly is a blackish invertebrate, with delicately veined wings that it folds over its body like a tent. It can be found near ponds and slow-flowing rivers; the larvae living in the silt at…

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.