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A REPORT ON MILL WOOD (GIBBS) PIT (THURROCK)
AND SOME REMARKABLE NEW RECORDS.
The area is part of the very large Chafford Hundred development which stretches from
Grays westwards to the famous "Lakeside" by the M25. At the present time I have
recorded the astonishing total of 40 Nationally Vulnerable, Rare and Scarce invertebrates,
mainly hymenoptera, here since last September. Mill Wood is a small remnant of
ancient wood with a public footpath running along its southern edge. Immediately to the
south of the wood is Gibbs Quarry, an old chalk pit. To the west and south of the wood is
an area of sandy ground with various degrees of chalky influence resulting in a variety of
flower-rich situations good for hymenoptera. The chalk comes to the surface towards the
western edge of the site by the Ockendon-Grays railway line. To the south-east of the
wood and east of Mill Lane is an area of south-facing flower-rich grassland and scrub
grazed by horses. The northern and eastern edges seem likely to represent unimproved
remnants of the former grasslands which must have existed in the area before they were
destroyed by the extensive quarrying that stretches all the way from Purfleet through to
Grays. These old quarries have themselves become excellent wildlife habitats, but many
have already been developed for industrial, retail or housing purposes. Apart from the
wood itself, all the Mill Wood area is ear-marked for Chafford Hundred housing
development and even the interest in Mill Wood would be destroyed by proposed new
link roads. There is some hope that these roads can be rerouted and that some of the most
important parts of the site can be kept as open green space.
The most important areas for wildlife seem to be Mill Wood itself, sand exposures to the
west and south of the Wood, grassland and scrub west of Gibbs Quarry with the grassland
on the southern slopes, the open chalky area alongside the railway line at the south-west
of the site where 1 recently found a colony of the Grayling butterfly and the grassland and
scrub east and south of Mill Lane.
Mill Wood is a small remnant of ancient woodland, with indicator plants such as Stinking
Iris Iris foetidissima, Wood Spurge Euphorbia amygdaloides, Sanicle Sanicula europaea
and Pignut, Conopodium majus. With the exception of the Stinking Iris these occur along
the southern edge of the wood and would be destroyed by the proposed building of a new
road in the place of an existing public footpath.
The southern edge of the wood is also very good for invertebrate wildlife because of the
plants that provide pollen and nectar sources and its south facing aspect. The footpath
and its edges is itself an important area for the nesting of solitary bees and wasps. I have
recorded the nationally rare and scarce bees Andrena proxima (Rare- RDB3) only the
second known locality in Essex, Andrena florea (Rare- RDB3) an obligate collector of
pollen from White Bryony which occurs by the side of the footpath at the western end of
the wood, Andrena trimmerana (Scarce- Notable B), Nomada fulvicornis (Rare- RDB3)
and Nomada pleurosticta (Scarce- Notable A). These bees were almost certainly foraging
here but nesting in sandy exposures to the west and south of the wood (in area H2(c)): I
have found the Andrena florea nesting in an exposure by the side of a path some distance
to the southwest of the wood with no other White Bryony apparently available as a pollen
source. Nomada fulvicornis is a cleptoparasite of the bee Andrena pilipes (Notable B)
and Nomada pleurosticta is a cleptoparasite of the bee Andrena labialis. I have found the
Andrena pilipes nesting in a sand exposure towards the southern end of the area and
Andrena labialis forages and probably nests on the southern slopes .
The nationally scarce spiders Philodromus albidus (Notable B), Philodromus praedatus
(Notable B) and Zilla diodia (Notable B) are present along the southern edge of the wood
on oak and scrub. In addition the fly Myopa buccata, a parasite of certain bees, was