They lay their eggs on exposed gravel, including roads and rooftops apparently assuming that no self-respecting predator would look there. As you can imagine, this strategy was developed before cars and tall buildings came about. Allaboutbirds.org describes the leap of faith required to follow the parents urging, including one instance of a set of chicks surviving the drop from a seven story building.
I can recall the first time I saw a killdeer. It put on its dramatic act, flopping around on the road with one wing apparently broken, an ancient dance similar to those seen in clubs today. I followed after it as it lead me away from where its chicks must have been. Then suddenly, convinced it had fooled me, it flew off. Although anatomically impossible, I would swear it had a big grin on its bill. If you have never seen the act, there are videos on on the web including this Youtube clip.
Francis Skalicky's weekly column never fails to enlighten. The whole story is at this News-Leader site.
