The Recorder – Nature Talk: Ducks, Geese and an Evolutionary Wonder

Published: 02/27/2022 16:00:43

Modified: 02/27/2022 16:00:10

It’s not always easy to remember how dependent we humans are on technology for every facet of our modern American life. We can easily take running hot water for granted and often forget how lucky we are to have fresh food available to us. Even more wonderful is the fact that we have built homes that are kept warm even when outside temperatures drop.

Last weekend, while visiting my brother-in-law, we enjoyed a temporary break from the cold by sitting outside on his patio and enjoying cigars with some good scotch. The uninterrupted conversation moved from topic to topic, like a hummingbird visiting different flowers in a garden, but one unmistakable theme was the cold of winter. Makes sense when you think about it because it’s been a cold winter, but even a moment of 50 degree temperatures didn’t allow us to forget the recent below zero nights we’ve had.

At one point during our time on deck, one of us brought up the idea of ​​being a soldier stuck in the cold. Valley Forge appeared, as did the Battle of the Bulge, and then we kind of shifted our focus to the birds that live around us. How do blue jays survive the cold? Even more amazing is the idea that there are birds that live their lives in the water even when the biting winter winds are blowing. How it works?

In this case, I knew the answer to that question. It’s something I learned when I was a student at UMass Amherst in the late 1980s and I’ve never forgotten it. It’s all to do with feathers and blood flow, but I think I need to slow down here and break down a few details to make it more clear.

First, ducks and geese and other waterfowl have feathers that are made waterproof by secretions from the oil gland, which is a structure located at the top of the base of the tail. During their preening sessions, ducks can often be seen nibbling on the feathers in this area, but what they are actually doing is activating an oil dispenser that produces chemicals that condition the feathers. Constant and careful attention to their feathers ensures that the birds are surrounded by an impermeable layer of warmth that prevents cold water from touching their bodies.

But then there is the question of the legs and feet of the birds. Without any feathers, how does this single patch of bare skin manage to come into contact with freezing water without killing the birds? The answer here is an evolutionary marvel; a heat exchange system that allows ducks to regulate their blood temperature to protect them from hypothermia.

The heart is located in the center of the body where the temperatures are the hottest. Warm blood goes to the lungs to pick up oxygen, then returns to the heart to be distributed throughout the body. A network of arteries carries this oxygen-rich blood to the head, internal organs and legs. As the arteries descend through the legs, they create a network of close contact with veins that bring cold blood back to the feet and this is where the magic of heat exchange does its work.

While warm blood from the heart goes to the feet, cold blood returning to the body cools it down. Simultaneously, cold blood flowing back to the body is warmed so that there is no shock to the bird’s core body temperature. This heat exchange is so efficient that ducks and geese can keep their feet healthy with oxygen and nutrients while minimizing heat loss. These birds can spend hours and hours in water that would kill a human in minutes. Even more amazing are the ducks that dive underwater to find their food every day during the winter. Science can explain it, but it’s still amazing that it works.

So the next time you find yourself curled up on a cold winter’s day, staring out the window and wondering how the little birds survive the cold, let your mind wander east where many species of ducks and geese spent every winter day floating in the coastal waters of the Atlantic Ocean. Just thinking about it makes me want to take a trip to the coast where I can find a restaurant that serves clam chowder and has a view of the water. Maybe I’ll see you there too.

Bill Danielson has been a professional nature writer and photographer for 24 years. He has worked for the National Park Service, US Forest Service, Nature Conservancy and Massachusetts State Parks and currently teaches high school biology and physics. For more information, visit its website at www. or visit Speaking of Nature on Facebook.

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