What is the primary purpose of the eclipse or basic plumage for female ducks?

The primary purpose of eclipse or basic plumage for female ducks is increased concealment from predators. During the molting period, when females lose their vibrant breeding plumage and take on a more subdued coloration, this transition is crucial for their survival, especially after nesting. The drab and cryptic coloration helps to blend into their surroundings, such as reeds and grasses, making it more challenging for predators to spot them and their young. This natural camouflage is essential during a vulnerable time when the females are focusing on protecting their nests and, subsequently, their ducklings.

The other options, while relevant to various aspects of duck behavior and ecology, do not accurately reflect the primary function of eclipse plumage. For example, attracting mates is more directly related to the vibrant plumage seen during breeding season. Territorial displays are typically linked to male ducks and their efforts to establish breeding territories, rather than the function of female plumage. Temperature regulation is a general physiological concern but is not specifically related to the role of eclipse plumage in enhancing concealment from predators.