Killdeer

@Marie-Hélène Ammor: Normally they are found only in pairs in the plains. I was surprised to see a large group.

@JamesC: I didn't know either and was surprised to see them in a flock as well.... normally, as you know, they fly low over the prairie.

@The Dark Dude: Thanks for that. Much appreciated. The call of this bird is said to be the sound of "kill deer." Frankly the bird is a prairie loner and the call very plaintive.