Emerald Lake, Superior National Forest, Minnesota. July 2010
Last week was vacation time, a proper get-out-of-town-for-at-least-several-days-and-go-someplace-special type of vacation, where James and I spent three and a half days canoing some of the lakes in the Boundary Waters Canoe Area Wilderness in northern Minnesota. This is the land of the French voyageurs, trappers and traders plying the waters and dealing with the local Ojibwa tribes for access to beaver pelts. With just a little imagination, the recreational paddler can put himself in their shoes, perhaps pretending that his Tevas are moccasins; the canoe may not be made of birchbark, but surely it was hand-assembled from locally grown Kevlar.
We had been on the water less than fifteen minutes when James called my attention to a certain bird call, which he nominated as the emblematic call of the Boundary Waters. I listened to it a few times, and finally realized, "That's a chickadee!" Except it's a long-winded type of chickadee.
The normal chickadee call, which you can hear here, is a slow, two-note whistle known as the fee-bee, like so:
or sometimes with a repeat of the bottom note:
Chickadees are common here in SE Michigan, and they were common in Yellowstone. In both locations, the calls were the same. But up in Minnesota, the calls were more verbose, invariably ending with a dotted-rhythm extension:
I've never heard this version of the fee-bee call anywhere else. But as we moved from lake to lake, I began to hear even more variants. There was the "Three Blind Mice" version, which began with two prefix notes:
And then there was the even stranger version, which began by jumping up a fourth:
I call this one strange, because of the ascending prefix. The others seem like smaller modifications of the base call - repeating the final notes, or adding another note in sequence. But adding a big step, when all other versions involve no more than a single full-tone step at a time, is a more radical departure.
I have no idea how that developed. But there you have it: a species displaying regional variations in vocalizations, which can fairly be called culture. I think the idea of culture in animals is no longer controversial among biologists, but it's still remarkable enough to be worth dwelling upon.
Also remarkable: the chickadee's fee-bee call is so musical that it can be rendered in our musical notation with pretty fair accuracy. The dotted rhythm I've noted above* is exactly as I heard it: in just as perfect time as a musician would perform it. The second note is almost exactly a full tone, and the unusual ascending prefix was almost exactly a perfect fourth. The reason you don't see bird calls rendered this way is because it's usually impossible. You won't hear many (if any) other birds that seem to have studied Western music.
* Using a program called LilyPond, which describes most of the lakes where I heard these calls. The actual call is at least an octave higher than I've indicted.