For the Birds Radio Program: Crows
Does the intelligence of crows set them at the pinnacle of avian evolution?
Transcript
(Recording of an American Crow)
The most intelligent bird family in the world is at the center of a controversy between European and American ornithologists. In the U.S., the crow is classified as a fairly primitive songbird. That’s why it’s in the middle of most American bird books–thrushes, vireos, warblers, sparrows, blackbirds, and finches are all believed to be higher up on the evolutionary scale than crows. But in Europe, the crow and raven are placed at the evolutionary pinnacle, above all other birds.
Why the discrepancy? Well, in the United States, ornithologists look at physical similarities between birds to show relationships. Crows and jays have a dense covering of feathers on their nostrils, similar to only one other family–the chickadees. So American scientists claim the two families are close relatives. Since fossils of chickadees have been found that are over 40 million years old, American scientists believe that crows, too, must be quite old.
European scientists put a lot more stock in birdbrains than Americans do. According to the British Ornithologists’ Union, the crow’s intelligence marks it as the most highly evolved bird, and so they ignore any physical evidence to the contrary. By their reckoning, crows are nowhere near chickadees on the evolutionary ladder.
Of course the crows don’t give a hoot who’s right–they’re busy with more important matters right now. Most baby crows hatched out last month, spent four or five weeks sitting in the nest, and are now busy following their parents around learning how to find food and stay safe. In all the years I’ve been birding, I’ve only seen a handful of crows killed by cars. Adults seem to spend as much time teaching their young about roadside safety as human parents do. In my observation, a pair of crows often splits up to simplify matters. In my neighborhood this year the two adult crows each seem to have custody of one fledgling, unlike the jays, who stick together and share all their duties.
Baby crows are as big as adults by the time they leave the nest. If you’re very close, you can tell them apart by their eye color–like many human babies, crows have blue eyes when they hatch, which change to brown as they grow older. Most of this year’s young crows still have fleshy tissue at the gape of their beak, making a wider, brighter target for their parents to aim food at. But the easiest way to tell young crows from their parents is to listen to them caw. Until a young crow’s voice changes in the fall, it sounds like this:
(Imitation of a young crow)
Adults have a raspy caw.
(Recording of an American Crow)
Henry David Thoreau wrote in his journal: “This bird sees the white man come and the Indian withdraw, but it withdraws not. Its untamed voice is still heard above the tinkling of the forge…It remains to remind us of aboriginal nature.”
(Recording of an American Crow)
This is Laura Erickson, and this program has been “For the Birds.”