The tightly packed, thistle-like purple flower heads of common knapweed bloom on all kinds of grasslands. Also regularly called black knapweed, this plant attracts clouds of butterflies.

Heather is also called 'ling'. Look for it on our heaths, moors and bogs, where its delicate, loosely arranged pink flowers attract all kinds of nectar-loving insects.

The muntjac deer was introduced into the UK from China in the 20th century. It has gained a stronghold in southeast England, where it can cause damage to our woods through browsing.

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.

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.

Despite its name, the large blue is a fairly small butterfly, but the largest of our blues. It was declared extinct in 1979, but reintroduced in the 1980s and now survives in southern England.

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.

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.

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 UK hosts a small, but important, breeding population of ruff. The ruff is a large sandpiper that is so-called due to the large ruff of feathers around the males' neck. This is used in a…

The common scoter has suffered large declines in the UK, threatening its survival here. Look out for this duck feeding at sea in winter when its numbers are bolstered by migrating birds.