Laura Erickson's For the Birds

(Recording of a Trumpeter Swan)

As the mother of a boy who is four and three-quarters years old and a girl who insists she is two and two quarters old, I have had to learn a lot about dinosaurs. I know that triceratops and stegasaurus ate plants, tyrannosaurus rex tried to eat them, struthiomimus ate dinosaur eggs, and dynonichus had huge claws on his feet which could rip out the insides of a brontosaurus–all the gory details of which utterly delight my supposedly innocent little children.

But, for a birdwatcher, what is most fascinating about dinosaurs is that they were really just four-legged birds–at least, that’s what some knowledgeable paleontologists consider them to be. There are some fossils of one creature called Archeopteryx whose skeleton was exactly like a dinosaur except in one critical feature–archeopteryx clearly had feathers. Birds are the only animals with feathers–that’s part of what defines the class. And archaeopteryx is the only known creature that has both feathers and a full set of teeth. So some scientists consider archaeopteryx more than just a bridge between dinosaurs and birds–it’s one link in a long chain of evidence that birds as we know them are just a flock of feathered, flying dinosaurs.

The issue was bandied about in paleontological circles when some scientists began to believe that dinosaurs, unlike typical reptiles, were warm-blooded. All of a sudden it seemed to make sense why some dinosuars looked so much like today’s ostriches–struthiomimus’s name even means “Ostrich mimic”. When some scientists put together what they knew about one dinosaur, stenonychosaurus, they concluded that it must have been so swift a runner that it was almost certainly warm-blooded, and may well have had an insulating cover of feathers. Stenonychosaurus is considered the most intelligent of all the dinosaurs, too–scientists think so not because they administered little fossil IQ tests, but because from its bone structure they could figure out what its habits must have been as an active predator, and what its brain size relative to its body size were. This dinosaur was probably more intelligent than any existing reptile–its intelligence was more similar to ostriches and other birds than to reptiles.

It’s interesting to see other parallels between dinosaurs and modern birds. Many duckbill dinosaurs, like corythosaurus, had hollow bone structures on their heads which may have served as resonating chambers for amplifying their voices. This would serve the same purpose exactly as the incredibly long, coiled trachea of the Trumpeter Swan.

(Recording of a Trumpeter Swan)

It’s hard to explain extinction to a little kid. Even if dinosaurs were really reptiles and not birds, it’s appealing to look at a tiny chickadee and imagine that it embodies the spirit–and maybe something of the body–of a lumbering brontosaurus.

(Recording of a Black-capped Chickadee)

This is Laura Erickson, and this program has been “For the Birds.”