from forty-four 10 km. squares in Essex, though within this range it is significantly more
local than its relative, S. striolatum. Since local populations are probably reinforced
annually by immigration, many of our recent records will undoubtedly be of migrant
specimens. Consequently, the distribution-map probably gives an over-optimistic
picture. Nevertheless, the status of S. sanguineum as a breeding species now looks
encouragingly secure, and is almost certainly continuing to improve.
Sympetrum striolatum (Charpentier, 1840) Common Darter
One of the commonest and most widespread dragonflies in England and Wales, this
species is also one of the most familiar in Essex. Until the observer is experienced in
field-identification, S. striolatum can be easily confused with its close relative.
Sympetrum sanguineum (see under S. sanguineum for distinguishing features). As with
some other species of dragonflies, some confusion can arise from colour-changes which
occur with age. Males tend to become darker red. whilst ageing females gradually take
on reddish colouration, starting with the median line along the abdomen.
On emergence, individuals tend to disperse away from breeding sites, and teneral
specimens are often found in sheltered places, such as woodland glades and rides well
away from water. The fully mature males tend to take up territories in potential breeding
sites, whilst the females remain more widely dispersed. The typical method of egg-
laying described in the literature is as with S. sanguineum: the pair, in tandem, fly with
undulating motion over the water or among the stems of emergent water plants, the
female releasing eggs as the tip of her abdomen is repeatedly 'flicked' into the water.
However. I have frequently observed females ovipositing 'solo' and also with males
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