Glow-Worm Hunt, Hambledon Hill

To the north of Blandford is the Hambledon Hill National Nature Reserve (ST 845 125). Managed by English Nature, this 192m high chalk hill is a prominent feature – its summit sculpted with concentric banks and ditches – the remains of an Iron Age hillfort. Near its highest point a Neolithic long barrow, some 5000 years old. The sketch to the right shows the present day arrangement of the two major banks that – with ditch between – made up the main defences of the hillfort.

The chalk slopes of the hill are ideal for Glow-Worms. Glow-Worms (Lampyris noctiluca) are not worms, they are actually insects. All stages of this beetle give out light, but it is brightest in the adult female when she is attracting a mate. The light is produced by a chemical reaction and can be switched on and off at will. Although only small (about 2–3mm) the little bead of blue-ish green light can be seen from many tens of metres in dark conditions.

This gallery shows a field trip in late July led by the English Nature site manager, on which some 75 people – in age from 1 to 60+ yrs old – up the hill from Child Okeford (ST 836 126) to watch the sun set and then 'hunt' for the beetle. The warm, still conditions of the evening were particularly favourable, with glowing females seen over large areas of the hill.