160 The Mammalia of Essex; a Contribution towards a
commonest of the order, appearing earlier and retiring later
than any other, and it is the species most frequently seen
by day. It is on the wing in mild seasons nearly up to
Christmas, when it finally retires for its winter sleep,
choosing almost invariably holes in and about buildings for
its home. The flight, unlike that of its larger relative, is
low, and well described by its common name, "Flitter
Mouse" ; the sheltered sides of buildings or hedges being
favourite hunting-grounds, no doubt in consequence of its
food, gnats and small insects seeking the same protection
from the wind.
Vespertilio Nattereri. Reddish-grey Bat.—This easily
distinguished species is reputed to be rare; in this district,
however, it is one of our commonest bats. Houses and
buildings are favourite hiding-places in summer; and in
winter, cellars, caverns (as under Colchester Castle), and
such places, are generally chosen. Occasionally bats are
brought to me late in autumn, drawn up in the buckets of
our deepest wells, and three out of four being of this species
I have good reasons for believing that the crevices in the
brickwork of the wells are occasionally chosen as hybernacula.
I hear the peculiar note of this bat, during its evening flight-,
more frequently than any other in the streets and gardens of
Colchester.
V. Daubentonii. Daubenton's Bat.—This also is not a
rare bat in this district. It has one character by which it
may be distinguished easily: the wing membrane extends
only to the distal extremity of the tibia, leaving the foot
free, instead of the membrane being continued to the root of
the toes, as is usually the case in other species. Daubenton's
bat has been well described as an aquatic species ; its habit
of haunting water, either stagnant ponds or running streams,
flitting with rapid vibrations of the wings a very few inches
from the surface, and apparently spending most of its time
of flight there, makes the description "aquatic" a just one.
Their usual habitats when at rest are in buildings. In
winter I find them, as did Yarrell, under our castle at
Colchester. Some that I have endeavoured to keep appeared