“It’s lovely weather for ducks” is a sarcastic idiom meant to convey that even when the weather is extremely wet and rainy, ducks, at least, are enjoying it.
Ducks, of course, don’t just spend time in the rain. They spend much of their life on water, whether it’s on ponds, lakes, rivers, streams, or out at sea. And they do so with seemingly no ill effects. A duck can even dive deep underwater and later emerge with its feathers unimpaired and ready to fly.
Ducks have evolved some specific traits that enable them to live on water. Although many other species birds share some of these traits, ducks have adapted particularly well to watery environments.
When you get in the shower, you’ll notice that it takes a few seconds for your hair to get fully soaked. This is due to the natural oils on your hair giving it some protection before the water can penetrate it. Ducks also protect their feathers with something called preen oil, which is produced from the uropygial gland located near their tail, and secreted through the surface of the skin via a papilla, a small protrusion similar to a nipple.
Preen oil is a complex mix of waxes, fatty acids, and wax-alcohols, and in some species of birds it has been shown to be antibacterial. Ducks rub their bills against the opening of the gland and then straighten and clean their feathers in a process called preening. In doing so, they distribute the preen oil across their whole body and wings, as well as the skin on their legs and feet.
The oil repels water and helps to waterproof their feathers. It has also been suggested that preening may increase the electrostatic charge of the feathers which adds to the waterproofing effect, although this is not supported by any scientific studies.
Although other species of birds have a uropygial gland and produce preen oil which helps protect their feathers, for example, when it rains, it is highly developed in ducks and other waterfowl such as petrels, gannets, and pelicans. Ospreys, which spend much of their time near water, also have a strongly developed uropygial gland. Research has shown that the more contact a bird has with water, the higher the mass of the uropygial gland is.
However, although preen oil offers some level of protection from water, its main purpose is to keep feathers healthy and maintained by preventing damage from exposure to the elements
Ducks have three types of feathers; the contour feathers which cover the body, the down feathers which provide insulation, and the wing feathers which help them fly. The contour feathers are made up of a visible hard, smooth, straight vane, and a soft, fluffy afterfeather or aftershaft, that is hidden beneath the vane, and together they act as a protective outer shell. Contour feathers are the feathers that give a duck its shape and colour and are its first line of defence against water due to their unique structure.
On each contour feather is a series of interlocking hooks called barbules that are located on the vane, which helps them repel water. As long as the feather remains dry, the hooks stay interlocked and hold the feather tightly together, creating a waterproof barrier that prevents water from seeping through to the down feathers underneath. If a contour feather gets wet, the hooks unlink, and the duck can use its muscles just under the skin to fluff up the feathers and shake off any water. The barbules also help trap air between the feathers and the skin which aids the duck’s natural buoyancy.
Aquatic birds, such as ducks, not only have contour feathers with more tightly packed barbules but also have more of them compared to terrestrial birds of similar body sizes. This makes them far more resistant to water. Sea ducks and diving ducks which spend a lot of time under water in search of food have the densest feathers of all duck species which also insulate them against the cold water, allowing them to stay warm even in freezing temperatures.
However, the stresses of flight can sometimes force the barbules to become misaligned so the vane of the feather splits which allows water to pass through. Applying preen oil to their feathers can help maintain the flexibility of the feathers and help prevent them from breaking.
Ducklings are precocial and hatch covered in down with their eyes open. They stay in the nest for a few hours but once dry, can feed themselves and will follow their mother to water for their first swim.
However, their down is not waterproof and their preen gland is not fully developed, so their mother must use her own preen oil to coat the ducklings so they can enter the water safely. Once wet, a duckling will instinctively begin to preen and rub its head against its oil gland causing it to start working until after about a month it no longer needs to rely on its mother for waterproofing.
If a duck’s feathers become waterlogged and are unable to repel water, it can be at risk of drowning because the feathers no longer trap air beneath them reducing its buoyancy and ability to float. Ducks with wet feathers will also find it difficult to keep warm.
Wet feather in ducks can occur primarily due to two reasons; reduced production of preen oil, and physical damage to the barbs on the feathers.
Loss of production of preen oil may occur if the preen gland gets infected. And as ducks age, they produce less preen oil so older ducks are more at risk of wet feather. Oil, detergents, mud, debris, sharp edges, mould, lice, and mites can all damage the feathers and prevent the barbs from working properly.
Ducks that live in very dirty environments with no access to fresh water are most likely to suffer from wet feather. If a duck is unable to clean mud off itself before it dries it will absorb the moisture into its feathers including the coating of preen oil.
Some ducks also get wet feather from over-preening. If a barbule is damaged the duck may preen itself to try and fix the problem, but this only exacerbates it and the feathers become more and more damaged.
If the cause of wet feather is simply mechanical damage then it may go away when the duck undergoes its next moult.
