Are Ducks Really Waterproof?

By author of The Duck Blog

An inside look at the act of preening

“Like water off a duck’s back” is a popular saying, and for good reason. Ducks are, in fact, waterproof, as water seems to roll right off of them. Hunters huddle in the blind trying to remain dry in the worst of weather; ducks and geese seem to almost be at play in such conditions. 

Once more, diver ducks and northern species seem to be able to tolerate nearly anything Mother Nature dishes out, as if refusing to migrate to warmer climates. What is it about waterfowl that enables them to survive, and thrive, despite not having the latest Gore-Tex gear?

The answer lies in a term called preening; the method birds use to maintain their feathers. A little investigating showed preening to be quite an intricate process, shrouded in debate among the scientific community, but nonetheless worth discussing in our constant pursuit to learn more about our quarry. 

Preening, as an act, covers a number of activities. Here, we’ll talk about ducks, but preening occurs in nearly all bird species, and the methods discussed likely are similar, if not identical, for most species of geese and other waterfowl. The preening method includes care and lubrication of the feathers.

As hunters, we’re guilty of not truly appreciating all that ducks go through. Unlike other game species, the life of a duck is one of constant motion and relocation, with cross-country, and sometimes even inter-continental flights occurring annually. For that reason, a duck’s body must function as a well-maintained aircraft.

Preening helps to assure that. Preening pintails

Observing ducks in the wild helps key us in. They seem to never rest, and are always either feeding, chasing each other or fidgeting. Such is the act of preening, where each individual feather is meticulously maintained. As ducks check and re-check their bodies, they are actually cleaning each feather, removing any insects or lice, re-aligning the feather to it’s maximum aerodynamic position and then conditioning it.

This conditioning is the subject of much of the aforementioned scientific debate. Ducks, as well as a number of other bird species, actually coat their feathers with an oily substance that attributes to their apparent waterproof bodies. This is done through the uropygial gland, better known as the preen gland.

The preen gland is located near the tail of a duck, has a small, nipple-like opening, and is covered in short tufts of dense feathers. Yep, what you thought was a butt, wasn’t.

A review of literature shows that this gland has been the subject of much scientific study due to it’s apparent mystical powers and, at one time, was thought to be linked to many unbelievable feats of nature, including poisoning the prey of falcons, or shooting a stinky repellent toward nest predators of a bird called a Hoopoe.

However, what we know for certain is that, by working the gland with their bill, ducks retrieve the substance on their head and face, and then spread it over their body. Such gives their feathers an shiny, oily appearance, and the unbelievable ability to shed water.

Throughout history, many scientific studies have been done to determine once and for all the function of the gland. In both redheads and mallards, preen glands were removed in a laboratory setting in newly hatched birds. The result were ducks with unkept feathers that struggled to carry out daily functions, and would likely perish in the wild. Interestingly, though, the birds seemed to recharge after each annual feather molt, functioning normally for a while until repeatedly wet.

In addition, lab birds without the gland showed deterioration of their bills, showing the preen gland may function for many aspects of overall health.

Getting back to birds in the wild, the act of preening is likely nearly as important in mating and courtship as it is in survival of the bird. As we know, many mammals put on showy mating displays, and the same holds true for most ducks. Often, the boldest males are the most successful maters, and those looks can only be attributed to proper maintenance and oiling of the feathers through preening. In addition, some mating pairs mutually preen each other, an act known as allopreening.

Ducks are fascinating creatures and, the more we learn about them, the better we will be at pursuing them. Besides, such info makes for great conversations in the duck blind. The next time you get a chance, take a day off from the hunt and just head to the park to watch. The life of  a duck is incredibly complex, and deserves the attention.