Northern Prairie Wildlife Research Center
One of the most discouraging problems encountered in batproofing has been the necessity to seal the last opening at night after the bats leave the house. This difficulty has been overcome by means of a valve-like device installed in the last exit(s) (Figs. 10, 11).
|Fig. 10. Constantine's batproofing valve-like device. The light-weight, pliable, collapsible tube overlaps the heavier, rigid base tube, to which it is attached with tape. (Illustration of D. G. Constantine)|
|Fig. 11. Constantine's valve-like device placed in various installations. Bats in the dark stippled area of the house interior are about to enter tube. (Illustration courtesy of D. G. Constantine)|
D. G. Constantine (personal communication), having observed that batproofing can be discouraging when bats are in residence because of the necessity for night work, described a method that enables the work to be done in daytime. "After all entries except the primary one(s) have been sealed, a one-way, valve-like device is installed in the remaining opening(s) permitting the bats to exit after dark but preventing reentry. The bats depart through a smooth tube. Because some bats could reenter by hunching their way up the tube, soiling its surface and improving traction, the tube's end should be pliable enough to collapse closed when bats try to reenter. The device can be left in position for prolonged periods to permit lethargic or hibernating bats to awaken and leave. It should not be used from 1 May through August, when young, flightless bats may be in the roost. In due course the tube should be removed and the hole(s) sealed. A patent covering relevant methods and mechanisms has been applied for and a manuscript is in preparation."