In general, male birds are much more colourful than females. The bright colours of male birds serve to attract mates, since bright coloration signals strength and vigour. On the other hand, since females typically bear the brunt of incubating eggs and raising young, their more drab, earth-toned feathers help them blend better into their surroundings to avoid predators.
This general evolutionary paradigm is illustrated here in this set of wood duck images. (Please click on image to view full size.) Whilst adult wood duck males have stunning multicolored iridescent plumage and red eyes, with a distinctive white flare down the neck, the wood duck females have a more drab, brownish colour that blends well with their surroundings, making them less easy to spot.
For other posts about ducks in this group, please view:
zafoid.com/post/view/11025
zafoid.com/post/view/8119
zafoid.com/post/view/803
