The all-black rook is a sociable bird, so can be spotted in flocks or nesting colonies, known as 'rookeries'. Unlike the similar carrion crow, it has a grey bill and 'baggy trouser…

The Notch-horned cleg-fly isa horse fly dark grey in colour, with grey-brown mottled wings and intricately striped, iridescent eyes. There are 30 species of horse-fly in the UK; this is one of the…

Barnacles are so common on our rocky shores that you've probably never really noticed them. They're the little grey bumps covering the rocks that hurt your feet when you're…

The common carp is a very large fish that is popular with anglers due to its size and fighting spirit. It frequents ponds, gravel pits and lakes, but is not native to the UK, being introduced in…

The glow-worm is not actually a worm, but a beetle. Males look like typical beetles, but the nightly glow of a female is unmistakeable - lighting up to attract a mate in the darkness of their…

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…

The striking black-and-white checks of the marbled white are unmistakeable. Watch out for it alighting on purple flowers, such as field scabious, on chalk and limestone grasslands and along…

A common spider of heathland and grassland, the Nursery web spider has brown and black stripes running the length of its body. It is an active hunter, only using its silk to create a protective…