THE SURVEY
Although the systematic observation of dragonflies in Essex was begun more than one
hundred and fifty years ago. there was no attempt to give an account of the Odonata
fauna of the whole county until the work of W. H. Harwood (1903). Even then, however,
almost all records were from the south-west and north-east of the county, together with a
few from the Maldon district and the Thames estuary (in modern terms, from about
eight 10 km. squares, out of a total of fifty-seven in the county of Essex). By 1950 the
literature included accumulated reports from numerous observers spread across Essex.
Still, however, large areas of the county, especially north-central and north-west Essex
(a total of some thirty 10 km. squares) remained wholly unrecorded. Recording between
1950 and the late 1970s brought in records from another eight 10 km. squares by the time
of the publication of D. Chelmick's (1979) Provisional Atlas. Large areas of north and
central Essex, however, remained entirely unrecorded.
The first edition of C. O. Hammond's superbly illustrated Dragonflies of Great Britain
and Ireland was published in 1977. It immediately led to a new and more intense interest
in dragonflies throughout Britain. A number of naturalists in different parts of Essex
began actively studying and surveying their local dragonfly fauna; E. P. Ryan in Epping
Forest, J. Shanahan in the Chelmsford area and myself in the north-east. J. Dobson. G.
White, D. Smith and others began independent studies which were quickly united
through personal contact and 'hearsay' into a county-wide survey. This process was very
much aided by the co-operation of the Biological Recording Centres in the county, and
also by R. Merritt of the national dragonfly recording scheme. By means of
correspondence, regular field trips and annual meetings, the field recording of the
growing number of participants in the survey was co-ordinated.
In the early days, efforts were made to obtain up-to-date information on the condition
of sites already known to be of importance, and on the status of the less common and
threatened species. Information obtained from the national scheme and from the Essex
B. R. C.s played an indispensable part in this. Initially, provisional maps were prepared
on a 1 km. square basis for each species known to occur in the county, and recorders
were encouraged to send in reports of all site visits, with dates, detailed map references,
species lists and any relevant information about the sites or breeding status of species
observed. From the early 1980s each season's pooled results were circulated in the form
of duplicated maps for each species, together with 'summary' maps indicating overall
coverage of the county, and numbers of species recorded from each 10 km. square.
It soon became clear that our maps showed more about the movements of our
dragonfly-watchers than it did about the real distribution of the dragonflies! From 1983
onwards a systematic attempt was made to ensure effective coverage of hitherto un-
recorded or under-recorded areas. By the end of 1983 recent records were available from
fifty-three 10 km. squares in the county. The remaining four un-recorded squares were
all in the extreme north and north-west. These squares would clearly be an important
target for the following year's recording. But additional knowledge of the dragonfly
fauna of the better-recorded areas suggested that a number of other areas remained
seriously under-recorded. Two provisional measures of the adequacy of recording of
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