Stone curlews are unusual waders with large yellow eyes - perfect for hunting beetles at night.

Considered Britain's most threatened butterfly, the high brown fritillary can be only be found in a few areas of England and Wales.

The stone loach is notoriously hard to spot - not only is it mostly nocturnal, it is also well camouflaged and can partially bury itself in the riverbed. It uses its whisker-like barbels to find…