little brown bat (Myotis lucifugus lucifugus)
CONFIRMATION STATUS: Not confirmed.
CHARACTERISTICS: This is a small to medium size Myotis, with glossy
fur that is a dark yellow-brown to olive brown. The face, ears, and
membranes are dark, with the membranes sparsely or not furred. The
total length is 85-98 mm with a wingspread from 222-269 mm. It has a
weight of 5-14 grams and the female is slightly larger than the male.
This species mates primarily in the fall, and there is delayed
fertilization until spring ovulation, after depart from the hibernacula.
Nursery colonies of several to 1000 or more females form in late April-
May in warm dark locations. The summer colony may disperse to
several hibernacula, and the hibernating colony may come from many
summer colonies. When not hibernating, these bats emerge to forage at
late dusk, and often repeat hunting flight patterns. They may use water-
ways, escarpments, even highways for orientation only. The mean life
expectancy of the males was 1.55 years and for females 1.17-2.15 years
(closer to 2.15).
DISTRIBUTION: Migration generally is north to south, but some in all
directions. There are 13 caves with 100-1000 individuals of this species
and eight caves with more than 1000. This species will roost in caves,
buildings, rocks and trees, under bridges, in mines and in tunnels. They
also may dwell in man-made structures. This is one of the most abundant
insectivorous bats in Virginia. They are found in all forested regions.
FOODS: Moths are a major part of the diet as well as midges, mayflies
and aquatic insects. Lactating bats select larger insects than males or
nonparous females. They are very effective at feeding in patches of
insects. They forage at about 10-20 feet over trees, lawns, pastures,
and about 1-2 meters over open water. They may sweep low over
water for drink before they begin foraging.
Crooked Run Valley