This explains why momma was sitting so tall in the last photo!

Killdeer chicks are "precocial," which basically means they can run around and hide from predators very soon after they hatch. This is vital for tiny birds born on open ground. This mom and dad killdeer eluded hawks and cats while they sat on this nest. Killdeer lure predators away from their nests by faking injury. They flop around on the ground and make pitiful noises. As soon as you get close, they fly just out of reach and repeat the process, until you're well away from their nest. I hope these little guys make it!