The white-letter hairstreak gets its name from the white lines that form a 'W' shape on its underside. It is an elusive butterfly, spending much of its time in the treetops.

This secretive bird is a member of the rail family, related to coots and moorhens. The breeding call, a rasping rattle, is given mostly at night, sometimes for hours on end.

The melodious song of the nightingale is the most likely sign of this bird being about. Shy and secretive, it sings from dense scrub and woodland, day and night.

A delicate, small plant of woodlands and hedgerows, wood-sorrel has distinctive, trefoil leaves and white flowers with purple veins; both fold up at night.

A recent colonist to south east England, the metallic-green willow emerald damselfly spends much of its time in the willow and alder trees that overhang ponds, lakes and canals.

Famed for its tapping in the middle of the night, supposedly heralding tragedy, the deathwatch beetle is a serious wood-boring pest. In houses, their tunnelling can cause major damage.

At night, the pretty, white blooms of white campion produce a heady scent, attracting feeding moths. Look for this wildflower along hedgerows and roadside verges, and on waste ground.