Beaver expert, inventor and entrepreneur Skip Lisle of Beaver Deceivers International will speak in Belfast and Liberty on how to install deceivers and other devices designed to protect human infrastructure, wetlands and beavers. His presentations Wednesday, Feb. 22, from 6 to 8 p.m. at Waterfall Arts in Belfast, and Thursday, Feb. 23, from 10:30 a.m. to noon at Ivan O. Davis-Liberty Library in Liberty, also will cover the ecological role beavers play in maintaining healthy ecosystems and keeping wetlands functioning.