Final answer:
The Killdeer engages in a 'broken wing' act to lead predators away from its nest, exhibiting an altruistic behavior that increases its fitness by ensuring the survival of its offspring.
Step-by-step explanation:
When frightened, a Killdeer "freezes" and its breast bands protect it because they help the bird blend into the environment, making it less visible to predators. However, if a predator gets too close to their nest, a mother killdeer will engage in a behavior where she pretends to have a broken wing and leads the predator away from her chicks. This act is a distraction display and is also considered an altruistic behavior because the mother killdeer risks her own safety to ensure the survival of her offspring. These actions increase her fitness by improving the chances that her genes will be passed on to the next generation through the survival of her chicks.