American Coots photographed at the White Rock Lake spillway.
Wikipedia has this to say about American Coots:
Much research has been done on the breeding habits of American Coots. Studies have found that mothers will preferentially feed offspring with the brightest plume feathers, a characteristic known as chick ornaments. American Coots are also susceptible to conspecific brood parasitism and have evolved mechanisms to identify which offspring are theirs and which are from parasitic females.