On the Road in Texas - Killdeer on the Run and in Flight

The birds at the Colvin Run Habitat in Northern Virginia are always willing to come and perch - which is not always good for the photography skills.
So, whenever I visit the Henderson Drive Habitat in Frisco, Texas, I hike to a nearby field and refresh my quick shoot skills with the killdeer.
You can find the killdeer wherever there is a flat field with a little gravel and some grass. Although they are part of the plover shorebird family, the killdeer does not require the shore to thrive.
Killdeer spend most of their day on the ground or flying just a few feet off the ground. They make lots of noise, so I typically hear them well before I see them. It is rare that I can get closer than 40 feet to them.
I spent an hour photographing these two killdeer. But, they exceeded their normal level of squawking when I came to specific location in a field of mowed grass (adjacent to the rough field of gravel and grass where I found them).
When I was near this specific spot, they squawked loudly, and would run and fly just far enough to make me interested in following them.
After they would ran a bit or flew a bit, they simply laid down in the grass (last photo). After about 15 minutes of this wild goose (or is that killdeer) chase, I finally figured out the purpose of the display.
So what did I discover? Stay tuned for the next posting.