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'Hawker' dragonflies include the larger species, which
characteristically cover a definite 'beat',flying
back and forth 'hawking' for their insect prey. The
second group, the 'Darter' dragonflies, are medium-
sized, but still quite robust species, which tend to
spend much of their time perched on the ground or on
vegetation, often with wings swept down and forwards.
Periods of rest are interspersed with short sorties
after prey, to 'see off intruders, or to pursue
potential mates. The damselflies, or 'Zygoptera'
are mostly small, very delicate species, which tend
to have a rather feeble flight. They rest in
vegetation with their wings characteristically folded
together, arched over their bodies, moth-like. Over
recent years a number of dragonfly species have become
extinct in the British Isles, and it is believed that
there are now only 37 species of British dragonflies.
Of these, survey work over the past few years has
revealed the existence of some 23 species in Essex,
8 hawkers, 5 darters and 10 damselflies.
Perhaps the most common of all the hawkers is Aeshna
grandis (the Brown Hawker), and we so far have some 72
records from 23 separate 10 km. squares (57 10 km.
squares are wholly or partly in Essex). The spect-
acular metallic blue or green 'Emperor' dragonfly is
another well-known hawker. This species is much more
localised, but is still recorded from 8 10 km. squares
in the county so far. The smaller, bottle-green
'downy emerald' (Cordulia aenea) is still more scarce,
so far recorded from one site only in recent years.
The commonest of the darter dragonflies is the reddish
or yellow/orange 'common Sympetrum' (Sympetrum
striolatum), which is a familiar sight from July until
well into September. So far it has been recorded from
29 10 km. squares in Essex. Its close relative,
Sympetrum sanguineum (the ruddy Sympetrum) is
distinguished from striolatum by a distinct narrowing
of the male abdomen in the middle, and by the completely
black legs in both sexes. This species is nationally
rather localised, and becoming scarcer, so it is pleasing