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Heath Fritillary Melitaea athalia in Essex: a review of its status and a report of its
exceptional second generation in 1999
GRAHAM BAILEY
114 Wenham Drive, Westcliff-on-Sea, Essex SSO 9BL
Abstract
The history and status of Heath Fritillary Melitaea athalia in Essex are reviewed, from extinction to
re-establishment, with reference to the conservation management needed to sustain the populations.
Ongoing monitoring during August and September 1999 revealed an exceptional second generation
at Hockley Woods; full details of this unique event are presented.
Current status and conservation management in Essex
Historically, Heath Fritillary has been recorded from a number of scattered sites around the county,
but it is believed to have died out as a breeding species about 1890. During the course of the 20th
Century, it has had rather mixed fortunes as a result of re-introduction attempts at a variety of locations,
mostly in the south of Essex. The butterfly was released at Hadleigh Great Wood in 1925, and this
colony thrived for several decades until its eventual demise in 1972. A further re-establishment was
performed in 1983 but this failed - the habitat was only marginally suitable and recommendations to
improve the situation were not put into practice. It was again re-introduced to the same woodland
area in 1997 (at Belfairs Nature Reserve which is owned and managed by Southend Council) after
an appropriate management regime was instituted and adequate amounts of the larval foodplant,
Common Cow-wheat Melampyrum pratense, were identified at the site. Small to modest quantities
of the fritillaries were noted during their flight periods in both 1998 and 1999. The coppicing, ride-
widening and mowing performed by the local council's contractors is supplemented by additional
clearance work carried out by a small number of volunteers during the winter, especially at Dodd's
Grove.
The species' first major success in the county in recent times stems from the introduced stock of
Heath Fritillaries released into the Essex Wildlife Trust reserve at Thrift Wood, near Bicknacre, in
1984, using stock taken from the Blean Woods complex near Canterbury in north Kent. This project
was initially extremely successful - the butterflies prospered here for several years before their
numbers levelled out as the habitat underwent natural succession. The numbers recorded have
improved again in the late 1990s, but the specific management here is certainly not typical - the
flight and breeding areas can be considered as cleared glades rather than true coppice plots. At
present there are two main areas within Thrift Wood that are looked after for the species, one being
managed by the Trust and the other by the Cambridgeshire and Essex branch of Butterfly Conservation,
both of whom organise winter work parties at the site. The principal maintenance of suitable habitat
involves cutting of the herbage in the autumn with either a reciprocating mower or a brush cutter and
then raking up the arisings and depositing them in neat piles at the edge of the glade. Further areas
are 'scalloped' into the woodland borders as is deemed necessary for the continued high densities of
cow-wheat.
At Hockley Woods, Rochford District Council is liaising with English Nature and Butterfly
Conservation regarding the coppice management regimes which are vital for maintaining and
increasing the viable habitats for the species. Apparently the species was introduced here back in
Essex Naturalist (New Series) 17 (2000)