Brood X Cicadas hatch every 17 years in the Northeast, and this is the year. Cicadas that have been underground for 17 years emerge and breed. The females deposit eggs on in grooves on tree limbs or branches. This can kill small branches, but doesn’t harm established trees. Nymphs feed on the tree in the groove, then drop to the ground where they burrow in and feed on the root. They feed on the roots and tunnel for 17 years, and then crawl up from the ground. They shed their skins and mature, mate, and this cycle starts again. When they emerge they are a feast for wildlife and if abundant produce a really loud chorus.
Enjoy the show, including the wildlife that are chowing down on them. The other thing to do is to net young trees with 1/4″ netting to protect them.