Backyard Biology

Nature stories from my backyard and beyond

Nature Stories

The Owl I Didn't See

Thursday, April 5, 2012

I went for a walk in the woods the other day. I didn’t see the owl. I know he was in the area since I have been hearing him hoot just about every night for the past month. He and his mate.

The woods behind my house is home to three types of owls that I know about - great horned owls, barred owls and screech owls. I know they are there because throughout the year, I hear all three calling. On one memorable occasion, I heard all three in the same night. But never in all my rambling through the woods have I seen an owl roosting in the tree during the day. The only time I see them is when they are pointed out to me by a flock of crows. It seems that crows don’t like owls much. When they spot one, they set up a call notifying all of the crows for miles around that they have spotted an owl. This call also lets me know of the owls presence. If I am lucky, I will arrive on the scene before the owl has had enough and left the vicinity. Then I get to see the owl. As I watch it sitting there, I wonder how it is that I can’t find them on my own. Such a large bird should be easy to spot. But they are not. At least not for me. The crows, however, seem to have no problem finding them.

I am no stranger to great horned owls. In my work as a science educator at the Museum of Science in Boston, I often bring one on stage to show our visitors. Sitting on its perch, the owl attracts a lot of attention. People walking by can’t help but notice the owl. owlSeems like an owl in a building is much easier to spot than an owl in the woods. So I thought I’d try a little experiment. I started asking the visitors to describe the owl. The answer I received most often was “beautiful”. People described the owl as a beautiful bird. Never once did anyone descibe the owl as colorful. Of course, the owl is a very colorful bird. It’s just that the colors run more to the earth tones - black, brown, gray. But when one thinks of a colorful bird, one thnks of birds that are bright red, blue, yellow or orange.

In the animal world, color serves a function. For many songbirds, that function is to attract a mate. The brighter the male, the more he gets noticed by the females. And even though he may be more noticeable to predators as well, that is an acceptable risk if it means he gets the girl.
Bright colors, however would serve no purpose in an owl. Owls do their courting at night, when it is dark. Colors do their work in the day, when it is light. At night, all colors disappear. So the color of an owl must serve its function in the daytime.

I thought to myself, what is an owl up to in the day. And of course the answer is sleeping. Owls sleep during the day. That means they don’t want to be disturbed by me, the crows or anything else during the day. Therefore, their colors must serve the function of making them not noticeable. But of course, as my experience with the owl at the Museum pointed out, owls are very notieable in the Museum during the day. However, owls are not usually found in a museum. Would they be as noticeable during the day sitting on a branch in a tree in the woods as they are on the perch at the Museum? This was pretty easy to test. I took a picture of the owl on the stage and replaced the background of the stage with the background of someplace the owl might like to spend the day sleeping - against the trunk of a pine tree. I showed these two pictures to the visitors to get their reaction. Click on the video below to see the results.

 

When placed against the proper background, the owl disappears. The colors are obviously for camouflage so they can get a good day’s sleep. No wonder I didn’t see the owl on my walk. Chances are pretty good that I walked right by the owl and never noticed him. I wonder how often that has happened. Has it ever happened to you? Have you ever walked by an owl and not seen it? Probably.

Now if I can just figure out how the crows find the owl!