Perhaps the most interesting thing to watch is when the incubating bird is flushed from the nest, the bird appears to have a broken wing(s) as if it can not fly. It also rolls and screeches to take the attention away from their ground next. It will almost act breathless. Meanwhile, the other partner flies and swoops and continues to protest until the intruder leaves.
It is said a law was past in 1918 protecting the Killdeer from being hunted for sport. The are not edible. They are, however, useful by destroying great quantities of noxious insects which includes mosquitos!
And just in case you don't know the difference between a loon and a kill deer, the loon has red eyes and the killdeer has orange. :) I am a wanna be birder. Before the move back to the north and attending the lake country, I had only heard a loon and had never seen a Killdeer. I have much to learn.