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A REPORT ON FERRY FIELDS, TILBURY
Ferry Fields are an extensive area of grazing marsh grassland south of the railway line
between Tilbury docks and Tilbury Fort. The site is yet another threatened area in the
county of great wildlife value. Virtually the whole area has been identified in the Draft
Thurrock Borough Local Plan as Employment land for New Development in Primary
Areas, despite its recognition by the Essex Wildlife Trust as a Site of Importance for
Nature Conservation in the county. The Local Plan has already been on deposit and
preparations are taking place now for a Pre-lnquiry Meeting on the 19th December 1994
and the Public Local Inquiry starts on the 7th March 1995.
The site consists of unimproved grassland grazed by horses and sometimes by cattle.
There are a number of dykes that may be of importance for their aquatic fauna. A public
footpath crosses the site from near Tilbury Riverside Station north to the main railway
line and south Tilbury. The flora is clearly quite rich, but I do not know if a detailed
survey of this exists. I started to look at the area this year but was very unlucky with
initial visits I made before August. Each time the weather was very windy and I had little
success looking for hymenoptera, my main target group. However in August I made a
number of visits that immediately demonstrated the importance of the site for
invertebrates.
My list includes a number of excellent invertebrate records: the Nationally Scarce large
robber fly Asilus crabroniformis is fairly numerous at the site, resting on cow or horse
dung. The larvae are believed to be predatory on the larvae of dung beetles (and
therefore the species needs the continued presence of grazing cattle or horses). It was
thought to be extinct in Essex until it was found at the nearby Broom Hill site in 1992 by
Roger Payne. 1 have also found it on the land to the east of the Tilbury power station but
these 3 sites are all within a small area. In August this year I also found the species in
small numbers at Eastbrookend, Dagenham Chase where there is an important area of
horse-grazed grassland in the Dagenham corridor.
The Nationally Rare (RDB3) aculeate wasp Passaloecus clypealis (confirmed by G.
Else) was taken along a Phragmites ditch on the western side of the site. It is known from
only about a dozen sites in East Anglia and south-east England including Benfleet and
Higham in the Thames marshes. It is thought to require wetland sites of high quality.
A reasonable number of the Nationally Scarce bumble bee Bombus sylvarum were found
foraging at Red Bartsia. This is a local and much declined species that is recorded from
the Thames Estuary but the only other site 1 have found it in Essex is
at the Wat Tyler Country Park at Pitsea (determined by the late John Felton). I also saw
what I believe was this species at Fobbing Marshes in August this year. Ted Benton
informs me that these appear to be the only records for Essex in more than 10 years.
Other Nationally Scarce species recorded are the bees Hylaeus cornutus, Lasioglossum
malachurum, Melitta tricincta and Spechodes reticulatus, the hoverflies Cheilosia
velutina and Volucella inanis and also Roesel's bush cricket.
FERRY FIELDS LIST.
Spider hunting wasps
Priocnemis exaltata Chrysid wasps
other spp. indet.
Chrysis cyanea