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.

This hefty diving bird is a winter visitor to the UK, where it can be seen around the coast or occasionally on large inland lakes.

During the breeding season, the common tern can be seen around our coasts and also inland at gravel pits, reservoirs and lakes. It nests in noisy colonies and can be spotted plunge-diving for fish…

Look out for the swallow performing great aerial feats as it catches its insect-prey on the wing. You may also see it perching on a wire, or roosting in a reedbed, as it makes its way back to…

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.