How can I protect my recorders from electric discharge?
Avoid mounting microphones on tall plastic masts (e.g. fiberglass, nylon, etc.) for deployments in dry conditions because a breeze flowing over the plastic can build up a sizeable electrical charge much like rubbing a balloon. Eventually, the electric charge will be strong enough to discharge with an attraction to the mass of metal in the mic cable, resulting in a spark that could damage the microphone or recorder. Instead, use wood or metal masts.
If electrical storm activity is a possibility, you need to protect the microphone and equipment from damage from electrical discharge. If the best path to ground is through the microphone and/or Song Meter, then the microphone and/or Song Meter can be severely damaged. To protect against this, like a lightning rod, you need to create a better and safer alternate path to ground. One way to do this is to use a pipe clamp to clamp a heavy gauge (18AWG) wire from the microphone to ground (e.g. by securing the other end of the wire to the metal frame of a grounded tower structure, or securing the wire to a metal pipe planted 2 meters into the earth). The connections must be electrically strong, with low resistance. A local electrician might be able to help you with a specific installation. Additionally, it is better to not ground the Song Meter or its power source so there is not a clear path to ground through the Song Meter.