If a large bat colony must be evicted from a wall or attic, careful observations should be made at dusk to find entry holes. The bats must emerge each summer evening to feed. The entry holes are also sometimes recognizable by stains around the holes or crevices used or by droppings beneath them. Once roost entrances have been located, the bats can be excluded. Again, this should not be attempted when flightless young may be present, which usually occurs June through August in South Carolina.
Most bat species leave in winter, permitting exclusion in their absence.
However, some bats hibernate in buildings, especially in warm climates, and when attics are heated. When this is the case, or when one does not wish to wait for winter, there is a relatively simple exclusion technique that can be used in fall, after young are flying but prior to the winter months. The netting can be obtained in quantity to cover areas of nearly any size. Using duct tape or staples, the netting can be hung during daylight hours above areas where bats emerge. A strip of netting at least two feet wide, hung one to two inches in front of bat exit holes, and extending at least two feet below and to the side of exit points, will allow the bats to emerge, but later they will be unable to find their way back.