How Ducks See: The Science Behind Waterfowl Eyesight
The mallards leap from their roost on the Susquehanna River, greeting the rising sun with an anxious chorus of beating...
The mallards leap from their roost on the Susquehanna River, greeting the rising sun with an anxious chorus of beating wings and excited quacks. They’ve been on the move constantly since departing Ontario, and find themselves desperately hungry and eager to find other feeding ducks. They are the perfect birds to kill.
As they bank back into the wind, there I sit, age 13, clutching a hand-me-down Remington 1100. The greenheads slice the air as they descend–how that sound tears me to pieces to this day–and in my youthful exuberance, I raise my hat brim to look. Thus ensues my first lesson in the wild duck’s powerful vision. Since flaring those mallards, I’ve often pondered how ducks visually process their environment. The science is fascinating. And understanding it can make you a better hunter.
The Eyes Have It
According to Ducks Unlimited, waterfowl can see two to three times farther than humans, thanks to powerful muscles that control the curvature of their corneas and lenses. In the human eye, only the lens can adjust. This remarkable adaptation suggests that a duck’s vision is by far its most powerful sense. It can see a lot farther than it can hear.
As hunters, when our goal is gaining the attention of migrators or passing flocks, perhaps we should ditch the hail call and focus our efforts on creating the most visible and realistic spread that our resources allow.
Waterfowl also have one of the most highly developed retinas in nature. A vast number of color-receptive cones within the retina help ducks form crisp images and spot the human form, but the trade-off is poor night vision.
Additionally, the retina sports a structure unique to avians known as the pecten–a high concentration of blood vessels that provides superior sensitivity to motion. So, waterfowl’s advanced retinas mandate that hunters remain still, keep hat brims low, and make a good hide.
Ducks and geese don’t see color the way we do. They see reds, greens, yellows, and blues more vibrantly–thanks to their retinas–plus an extra set of cones allows them to see ultraviolet radiation. This gives them exceptional light sensitivity; as a result, shine and glare are the duck hunter’s enemy. Whether it’s a blued shotgun receiver or a pale, exposed face, waterfowl are adept at spotting unnatural reflection.
This aspect of waterfowl vision appears to be driving much of modern decoy design, with the trend continuing toward fully flocked models and UV-dulling paints. However, decoy makers have their work cut out for them: DU says that juvenile drake pintails, for instance, don’t even have the same UV signature as adult drakes.
This color and UV-light sensitivity has also led to the design of at least one new camo pattern: GORE Optifade. Rather than replicating vegetation, the pattern consists of swirled hexagons and other shapes designed to disrupt the ducks’ senses of motion and color. Though I doubt any camo will completely hide a fidgeting hunter, it’s an intriguing concept.