[Cazador]

Evolution works by chance mutations that result in appearances (phenotypes) or functions (physiology) that give the affected individual a competative advantage and allow them to survive and reproduce more efficiently that those lacking the beneficial mutation. Mutations that aren't beneficial can either be neutral or harmful, but there is no "intent" in it... only chance events that may have beneficial, neutral, or harmful outcomes. If birds use the red coloration as a warning signal, then there is a second (perhaps linked) advantage that comes with the change in the ion transporter's mutation. Beyond that, I don't know if other predators, like dogs, cats, coyotes, raccoons, etc. use the red coloration as a visual cue.