Waitwaitwait. I think I've got it. It's the beak, right? It's totally the beak. No? Well in that case, I have no idea – it looks like your standard-issue Piping Plover/centipede genetic hybrid to me.
Top photo by Michael Milicia via awkwardsituationist– see more of Milicia's gorgeous photography on his website.
a mother piping plover on massachusetts’s plum island plumps her feathers to provide warmth and protection to an increasing plurality of her chicks, giving new meaning to the phrase “a bird in the bosom”. photo by michael milicia
This method of brooding is common to plovers, as is the downright remarkable behavior seen here on the left. What you're looking at is a diversionary tactic known as the "broken wing" distraction display. When plovers with offspring detect the presence of a predator, they will distance themselves from their newly hatched progeny and pretend to have a broken wing. [Gif adapted from a video by Dan Frieday, via View From the Cape]
Biologists theorize that by feigning injury, the parent is attempting to draw attention away from its chicks – putting itself in immediate danger so that its offspring (and genetic information) might live to see another day. Below, a red-capped plover can be seen faking a wing injury after the videographer happend by accident upon its nest:
In this video, a Wilson's plover can been seen feigning a broken wing in order to distract an Eastern Coach Whip Snake skulking about in the grass:
More info on clever, clever plovers here.