48
THE ESSEX NATURALIST
unkempt corners of gardens, Juncus and areas of tall grasses.
The Essex salt marshes are an important refuge for this species;
there are several records for Mersea Island (but these are not in-
cluded on the map as an exact grid reference is not available).
G. Abbott records the animal as being found in Agropyron pun-
gens behind the sea wall in North Essex. River valleys with their
tall marsh vegetation are also important; the Lea Valley has
been studied extensively, but all the known sites here (except
that at Rye Meads Sewage Farm) are to be destroyed by the
Regional Park development. The species has recently been found
on Whitehouse Plain in Epping Forest by K. Hoy in an area
covered by Deschampsia; in such an area it is even harder than
usual to locate Harvest Mice since their most obvious signs, the
nests, tend to be hidden at the base of the grass tussocks and are
extremely inconspicuous. The other plains in Epping Forest
would certainly repay investigation and more sites for this
species may yet be found here.
It would seem, therefore, that the Harvest Mouse is widely,
but locally, distributed in Essex and that its apparent rarity is
due to the difficulty in locating this species. Apart from the de-
cline in cereal crop populations there is no evidence to support
the view that it has declined in abundance in recent years, and
seems to be found whenever suitable habitats are closely investi-
gated.
Wood Mouse (Apodemus sylvaticus (Linn.)) Map 6
Laver: "Common everywhere in Essex . . . , one of the most
destructive of its race in fields, gardens and plantations. Plots
of newly sown peas or corn are especial objects of its attention
It is rarely found in houses, barns or ricks, much preferring the
shelter of the hedgerow or wood."
This species can still be said to be common almost every-
where in Essex. Table 5 shows that it was found in nearly 90%
of trapped habitats and about 60% of those areas investigated
in the 1968 bottle-survey (when Apodemus remains were specifi-
cally identified). Wood mice are often common well away from
woodland, one of the highest catches being in a field of chick-
weed and thistles near a sewage farm. This species has been
found in urban gardens and on waste ground well into east
London. The results of the Coptfold survey indicate that a
large population builds up in crop fields, especially cereal crops,
and that these migrate into woodland at harvest time. To the
list of agricultural crimes given by Laver can be added the re-
cently reported large scale attack on newly sown sugarbeet.
Yellow-necked Mouse (Apodemus flavicollis (Melchior)) Map 7
This species had not been identified in Essex at the time Laver
wrote his Special Memoir. The first report in Britain was pub-
lished by de Winton in 1894. recording it as a species distinct