Thursday, November 27, 2014

Murmuration



Murmuration may not be a familiar word, but it describes the low, continuous, indistinct sound large flocks of birds make either with their voice or the sound of their wings flapping. The word is most often associated with starling flocks although there are plenty of other birds that do the same thing. Think enormous flocks of geese in places like the Bosque del Apache National Wildlife Refuge, or the sandhill cranes that gather on the Platte River, or Flamingos in Africa. If you would like to see some amazing footage, google "starlings," "YouTube," and "Rome" or "Italy."


On the vast majority of mornings at the Patuxent, there is very little noise. You might hear a cow lowing in the far distance or a boat engine down river somewhere, but for the most part, it is very quiet. A couple of year ago in the Fall, I was filming from a dock when all of a sudden there was a startling noise coming from the direction of the marsh across the river. Part of what was so startling was that it could be heard from a distance of about a quarter mile away. I had never heard anything like it. It was nothing less than the sound of a million wings; wings in such numbers that they could be heard from that distance. I had been there for more than an hour and there had been almost no noise in that time, so I had no idea that flock was even present.

These two pictures do not do this flock justice. I had a telephoto lens on the camera which only covers a very narrow 6-7 degrees (holding your arms straight out from your sides covers 180 degrees). There were probably ten times or more birds than can be seen in these two images. The sound was not their voices, but the beat of their wings and it became thundering when they flew directly over me. It was incredible! I have never experienced anything like it.


In a murmuration, the flock responds almost as a single organism within a split second, changing directions and often having exactly the same body attitude as all the others. How the flock communicates when they are flying like this fascinates scientists.

When I was a kid, my family had a flock of ducks. They were species known as Muscovy's and they didn't quack. They had kind of a breathy whisper. We lived on a dairy farm and every evening the family would lead the ducks down to the pond to swim. They would be scattered all over the pond but at the same split second (I mean like snapping your fingers), they would all dive below the surface (without having made a sound) and race around underneath the water for half a minute or more. Then, in the same split second again, they would pop back up on the surface. How they communicated their intentions was a mystery, but it was fascinating to watch. It happened every evening.


One longstanding question that I have had and have never seen addressed is, Why do birds (especially blackbirds) gather in large flocks over the Fall and winter? This photo was taken at a different time over the marsh at North Beach. It seems counter intuitive to me to be gathering into huge flocks where competition for food is enormous at a time when resources are at their most scarce.

Just a few decades before the passenger pigeon was declared extinct, a single flock would darken the skies over the course of several days over cities in the south. They numbered in the billions with a "B!" How incredibly sad that our race wiped them from the face of the earth, largely because of greed. They were once thought to be the most numerous bird in the world, making up one quarter of all birds. The flocks I have seen are nothing by comparison. How awesome it must have been to see such an event.

A typical flock of mixed species on our lawn

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