NOTES ON THE MAMMALS OF ESSEX
181
seem to overlap to any great extent, for the Field Mouse tends
to keep to the more open parts of woods, whereas the Bank Vole
prefers the rather thicker undergrowth.
Short-tailed Vole: Microtus agrestis hirtus (Bellamy).
Although rather less common than the Bank Vole, this is the
animal of the well-known vole "plagues"—one in the Southminster
area in 1580/1, and one in the Rochford and Foulness area in
1648. This species tends to be confined to areas having thick
grassland, for it makes its runs and nests among the grass roots.
Thus it is abundant on Skipper's and Foulness Islands, and is re-
corded from Dawes Heath, near Southend, and from the Colchester
area. It is present in smaller numbers in the areas of Dunmow,
Margaretting, Chingford, Romford, and Walthamstow, for in these
regions the woods and copses seem to encourage the Bank Vole
rather than the Short-tailed Vole. The species is also found in the
grassy areas of Epping Forest and in the surrounding small woods
where there is sufficient grass cover.
Water Vole: Arvicola amphibius amphibius (Linnaeus).
Care in identification of this species is necessary in order to
avoid confusion with the Brown Rat, which also may be found
living in an aquatic habitat. In general, the Water Vole is more
vegetarian in its diet, and may cause considerable damage to
willow stools, as it did in a nursery at Fordham (C. Owen in litt.).
The species probably occurs widely in aquatic habitats, and has
been seen at Bradwell, Great and Little Baddow, Galleywood,
Althorne, Dunmow, Abridge, Snaresbrook, the Epping Forest area,
and the Colchester district, although it is curiously scarce in the
Flatford Mill area (c. 1951).
Long-tailed Field Mouse: Apodemus sylvaticus sylvaticus
(Linnaeus).
One of the species taken in considerable numbers in Longworth
traps, this mouse is recorded from a wide area. Chigwell, Dun-
mow, Havering, Abridge, Chingford, Margaretting, Romford,
Skipper's Island, Foulness, and Colchester are all areas where the
mouse occurs. It is stated to be common in suburban gardens.
Insofar as Longworth trapping gives an index of its occurrence,
it seems to be as common and as widespread in south and central
Essex as the Bank Vole, 106 individuals having been taken to date
in that region.
Yellow-necked Field Mouse: Apodemus flavicollis wintoni
(Barrett-Hamilton).
There are few records in The Essex Naturalist of this species,
a mere four records in the entire history of the Club. Trapping
results have suggested that while by no means a common animal,
it is far less rare than might once have been supposed. There
is a small colony centred on Easton Lodge, Dunmow, and it has
also been recorded from Abridge, Havering, Billericay, Bishop's