Birds that Swim in Cold Water

Birds that Swim in Cold Water - Ducks on Ice

Scientists have only recently come to understand many designs in nature. An interesting example is how birds that swim in cold water survive without hypothermia. The feet of ducks, gulls, loons, and geese show an example of incredible hidden design.

In these birds, arterial blood enters the leg and cools down. On its way to the heart, ventral blood picks up the heat released by the arterial blood in a process called “countercurrent heat exchange.” A mesh of arteries and veins called the “rete mirabile” (Latin for “wonderful net”) surrounds the blood vessels and amplifies the heat exchange. This arrangement limits the amount of heat the bird loses, saving it from having to use energy to reheat the blood. When you combine this discovery with the design that allows them to stand on one leg, you see how they are ideally suited to live in cold climates.

It is truly remarkable that virtually all climate zones have life forms perfectly designed to live in them. God created life to fill the whole earth regardless of climate conditions. Romans 1:20 says, “We can know there is a God through the things He had made.” Birds show the design of living things that radiates the wisdom and knowledge of the Creator. The foot design of birds that swim in cold water is just one great example of that.

— John N. Clayton © 2023

Reference: Audubon magazine winter 2023, page 52

Ducklings Swimming in Single-File – It’s Because of Fluid Dynamics

Ducklings Swimming in Single-File

We live on the riverbank, and many geese, ducks, and swans swim by our house daily. I have always been curious about why waterfowl tend to swim in a line each time I see ducklings swimming in single-file behind their mother. Researchers at the University of Strathclyde in the U.K. have applied a mathematical and numerical model to find an explanation.

For example, the swimming of the mother duck sets up an interference pattern reducing the wave-drag and propelling the trailing duckling forward as it surfs the wave. In this way, the lead duckling swims in the “sweet spot” behind its mother. With the rest of the ducklings swimming in single-file, the “wave-riding” benefit carries further. After the third duckling in line, a “delicate dynamic equilibrium” is reached in which each duckling acts as a “wave passer,” passing on wave energy to the next one behind without loss of energy.

The lead author of the study is Zhiming Yuan, and he gave the researcher’s description of this design by saying, “It’s so beautiful.” He thinks that there could be applications for maritime technology with shipping firms designing their vessels so they can travel like ducks in a row to reduce fuel consumption.

It seems that evolutionary natural selection would have terminated this arrangement. An eagle wanting a duck or goose meal would have little trouble picking off ducklings swimming in single-file behind their mother. If the birds were moving in random arrangement around their mother, it should be far more difficult to focus on and pick off one of them. Survival of the fittest doesn’t seem to apply to the behavior of the birds that use a single file approach to travel.

We see that this design is built into the DNA of these birds to provide conservation of energy which is critical to their survival. When you look anywhere in the natural world, you will see extraordinary design to allow living things to exist and thrive.

— John N. Clayton © 2021

Reference: The Week, November 5, 2021 page 21. You can find the original scientific report HERE.

Why Birds Stand on One Leg

Why birds stand on one leg
Have you ever asked why birds stand on one leg? We live on a river that has a massive number of ducks in it. When the ducks are resting on the edge of the river, they generally stand on one leg. When guests visit us, they want to know why. Ducks are not the only birds that stand and even sleep on one leg. Geese and Flamingos do the same thing.

The answer to why birds stand on one leg seems to be a simple matter of the application of basic physics. For an object to be stable, its center of gravity has to be directly above the point of support. In my basic physics classes, we have some demonstrations of that principle. A spinning bicycle wheel will do strange things if its pivot point is not under the center of gravity. A top that is not symmetrical will invert when spun with its round side in touch with the table. There are toys that appear to be suspended in space, but in reality, their center of gravity is located at one end which makes it look odd when it is on the edge of a table.

When you stand on two legs, your center of gravity is somewhere between the legs. That may sound stable, but in reality, it isn’t. When you stand, you waver as your body senses that any movement you make throws you off balance. There is a constant muscular effort that counteracts this movement. Just standing for a long time can be fatiguing because a lot of energy is expended to counteract this wavering.

Recent studies with flamingos show that when they stand on one leg, the center of gravity falls directly over the point that touches the ground. Standing on one leg, the bird’s body is quiescent. When the bird is on two legs, there is more muscle movement and the center of pressure on the foot touching the ground changes. If you look carefully at a duck standing on one leg, you will see that it stands a little lopsided, so the mass is completely above the point of support. In addition to energy conservation, standing on one leg allows birds to withstand cold temperatures by keeping one leg close to the body. So thermoregulation is also involved in this odd-looking design.

So if you have ever asked why birds stand on one leg, remember this. Anytime we see something in nature that we don’t understand; it is almost 100% sure that there is a design feature involved. What the animal is doing may look strange, but it has at least one significant function. Truly we can “Know there is a God through the things He has made” (Romans 1:18-20).
Data from Science News, June 24, 2017, page 15.
–John N. Clayton © 2017