The babies are 4 weeks old. They are fast when they run and they can fly. We have been invaded by the 17 year cicadas. They are a locust which lives underground and feeds off the sap from the tree roots. They emerge from the ground every 17 years and live about 5 weeks. Long enough to mate and lay eggs. They emit a loud whirring sound. When we go outside it sounds like a weird alien, science fiction movie. It is so loud.