Give the kids a remote control car/truck. Disguise it with a fox head or something. Some of those kids can steer those high speed RC vehicles faster than you can see. Have them chase the geese around and make them leave. If they go in the water, fire up the RC boat and continue the chase around the pond.

Or buzz them with a Radio control helicopter or drone. Those drone engines and the RC engines have a very annoying whine to them.

buzz them with those RC flying machines every night for a while. Then record the engine sounds and all you have to do is play the sound back through a boom box and when they hear that whine coming closer and closer they will head for cover!