Hector and I were lucky enough to see wood ducks when we visited the Jug Bay Wildlife Sanctuary over the weekend. Jug Bay is a mere 20 miles east of D.C. and well-worth visiting if you have the chance.
Wood ducks are dabbling ducks who like to eat a wide variety of things. The ones we saw were gorging themselves on acorns.
Acorns seem like an odd choice for an animal with no teeth, don’t they? It seems like ducks wouldn’t be able to crack the shell of an acorn to get to the food inside the shell, doesn’t it?
The secret is in their tummies, specifically their gizzards, which are specialized stomachs that can grind up food. Wood ducks are not the only animals with gizzards – all birds have them, and their ancestors, the dinosaurs, had gizzards as well. Gizzards are what make eating something hard and partially undigestible, like an acorn, possible for an animal with no teeth in its mouth.
A wood duck swallows an acorn whole and then the shell is ground off inside the duck’s body: the textured, muscular walls of the gizzard act like teeth, allowing the duck to separate the digestible nut from the undigestible shell. Isn’t that fascinating?