For the Birds Radio Program: Bell's Palsy
Laura talks about how birds use facial expressions and why Bell’s Palsy would be even harder for birds than for her.
Last week, out of the clear blue sky, the nerve that feeds the muscles on the left side of my face suddenly decided to go on strike. I first noticed it when I was trying to drink a cup of coffee—I couldn’t stop dribbling on the left side. Then I noticed I couldn’t wink my left eye, and even when I tried closing both eyes the left one stayed slightly open. So we headed up to St. Luke’s emergency room where my fears of a stroke were put to rest. To my great relief, it turns out I have a simple condition called Bell’s palsy. It presents a few difficulties—without control of face muscles, I can’t whistle, making it hard to call my dog Photon or communicate with my neighborhood chickadees. Drinking and eating are more difficult than usual. My non-blinking eye gets dried out easily so I have to tape it shut at night, and the two eyes aren’t working well together, so the other eye seems to be getting strained. But overall, I’m so relieved that it wasn’t a stroke that this doesn’t seem too horrible a thing.
We humans are capable of some 2000 facial expressions. Birds don’t use their faces quite the same way, but many species do control their facial and head feathers via skin muscles to communicate with one another. Much as we control our facial expressions, Blue Jays can voluntarily control their crests to show whether they’re feeling calm and relaxed with friends and family or whether they’re alarmed or annoyed or territorial. I’ll never forget when my education Blue Jay Sneakers was with me at a presentation. While I was speaking, the next speaker came into the room with his education Great Horned Owl. Sneakers had never seen such a terrifying sight and up went her crest. I continued to talk, and when she turned to look at me, she calmed down, relaxing the crest. But then she peeked over at the owl again, and up went the crest. Back and forth went her head, and up and down went her crest for many long minutes—a funny yet enlightening sight.
As humans do, birds communicate with a combination of body language and vocalizations. That’s why it’s so frustrating for birds to encounter their reflection in a window or mirror. Usually when a cardinal or robin intrudes on another’s territory, the original territory holder makes a couple of warning calls and erects his head feathers and the intruder flies away. The territorial holder often breaks into song for a while, and then sometimes checks just to be sure the intruder is gone. If he’s still around, the territorial bird virtually has to do anything more than raising his head feathers and making a sharp call note to send the intruder on his way for good.
But when the intruder is a reflection rather than a real bird, he doesn’t follow the program. When the real cardinal or robin sings, the intruder doesn’t sing back, which proves that he doesn’t belong in the area. When a bird doesn’t have his own territory, he not only is quiet, but also keeps his head feathers lowered to indicate that he’s not trying to pick a fight. But when the real bird raises his head feathers, the reflection does, too, which shocks and upsets the real bird. The bizarre facial reactions of the reflection compared to a real intruder contribute to the frustration the poor cardinal or robin feels, and very often it will get fixated on driving the reflection away, which never turns out well for the bird or for the frustrated people on the other side of the window. It’s a genuine mercy in these cases to paper over the windows long enough for the bird to start focusing on nesting again.
Fortunately, I don’t need to defend my property with my facial muscles, so Bell’s palsy won’t affect me as much as it would affect a bird. It’s hardly a horrible problem, though frankly, if I had to have a case of Bell’s anything, I’d have much preferred Bell’s Vireo.