Why Do Ducks Get in a Row?

The River Thames is beautiful in early summer, and the stretch just upstream of central London is full of birds: motionless herons watching for fish, bustling moorhens poking around the submerged plants, and watchful flocks of preening swans. But as my canoe club paddles along the river, we’re always looking out for our clear favorites: the mother ducks with a fluffy cluster of ducklings tagging along behind.

When they’re lingering at the shore, it all looks slightly chaotic, with baby birds dawdling and exploring as the mother duck keeps an eye on them. But when it’s time to move on, chaos shifts into order as the ducklings line up behind the adult and the convoy moves off together quickly and in perfect formation. It’s mesmerizing to watch, and it’s not accidental. This is all about saving energy.

Swimming is hard work, because water is dense and slightly viscous. At the surface, a large part of the resistance to movement comes from the waves that are produced behind whatever is moving: its wake. This is the familiar wedge-shaped wave pattern that we see behind ships, canoes and ducks alike, and all of those waves carry energy. If you move along the water surface, those waves are always continually generated and so the swimmer needs to put in enough energy to create them. This energy cost is felt as a resistance to movement. There’s also resistance because the water touching the ship or duck is pulled along too, creating additional drag. [Read more…]

Miracle. All of it.

Spring has finally arrived, and it makes me smile every time I step outside. New green leaves are pushing themselves into the sunlight as plants build the solar panels that will fuel them throughout the year. The first spring flowers are already in bloom, and a bright showcase of cheerful rainbow color is rapidly replacing the gray-brown palette of late winter.

I love the constant small surprises as new flowers appear. But each new sighting makes me wish for a superpower: the sort of expanded vision that could show me all the colors these flowers have to offer. Human beings can see some of them, and birds and bees can see a little more. But the potential range of invisible colors is mind-boggling, and science is only just starting to get a grip on it.

Our color vision is neatly summed up in our perception of a rainbow, sweeping from red, the longest wavelength of light that our eyes can detect, to violet, the shortest. But we can’t detect each shade individually; in order to make sense of this continuous spectrum of colors, we use a clever shortcut. Our eyes have three types of cone cell that respond to different colors—red, green and blue. Our brain figures out how much of the light that we see falls into each category, and it recombines that information to construct the myriad colors that we register. It is both beautifully efficient and frustratingly crude…

~Helen Czerski, from Colors That Only Bees and Birds Can See


Notes:

  • Photo: Spring Flowers by Paul.
  • Related Posts: Miracle. All of it.
  • Inspiration: Inspired by Albert Einstein’s quote: “There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.”
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