In some ways, they're real stupid. But on the other hand, their eggs are very well camouflaged from predators. And if you approach the nest or the babies, the adults put on an elaborate act of being injured, and lead you away from the nest. They drag a wing, repeatedly fall down, and make a pitiful sound like they're in pain. They let you almost catch up to them, then they fly away.
Listen to a killdeer.