Considered to be one of the prettiest gentians, the Chiltern gentian is a rare plant in the UK. It likes chalk grasslands, its purple, trumpet-shaped flowers blooming from August.

The black-tailed skimmer is a narrow-bodied dragonfly that can be seen flying low over the bare gravel and mud around flooded gravel pits and reservoirs. It is on the wing from May to August.

A stocky, little sandpiper, the knot can be spotted in estuaries from August onwards, migrating here from the Arctic where it breeds. Look out for it probing the muddy sand with its specialised…