But of course there are many factors that influence animal behavior, including a mother's willingness to risk her own life to protect her young. The desire to pass along your genes is a powerful force, and the Wisconsin research, which still needs to be verified by others, is only part of the picture.
"This is part of the puzzle," Gammie says. "But I don't think we have all of the pieces together."
There's one thing he's sure of, though. It's not a good idea to mess with a new mother, regardless of the species.
When he was living in Seattle a few years ago he was dive-bombed by a crow. The crow screeched as it dove repeatedly toward his head, and so naturally he kept looking up. A glance around his feet told him why the crow was being such a devil. Her chicks were near him on the ground.
"There's only a brief period each year when the chicks are on the ground," he says, and the black bombers had the right idea.
"Their behavior is really effective because it gets your attention away from the chicks," he says.
By the way, a few weeks ago I was walking my border collie when a ptarmigan bounded out from under a bush, making a terrible scene. It flapped its wings furiously, puffed itself up, and charged at the dog.
A few days later, I found out why. While walking along the same road I spied the bird, accompanied by four chicks.
My dog was unhurt, although a bit mortified over getting beaten up by a bird.
But at least it was a mother bird.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.