Killdeer

When Joshua was just switching from Cub Scouts to Boy Scouts, we started attending meetings at a church building that had landscaping rocks all along the side next to the parking lot. Every time we arrived at the building there would be a bird on the ground, running along and screeching at us. I asked about that. The Scoutmaster said, "Oh, there's a killdeer that nests in those rocks every year, and she's warning us away from her eggs."
I thought that was amazing; she was persistent, and the Scouts never bothered her or her nest.