Dec 12 2012
There’s a bird I want to tell you about but his lifestyle involves words so unusual that we have to learn a new vocabulary before I can introduce him.
The bird eats copepods and is fond of polynyas.
What the heck is a copepod?
The word “copepod” actually describes the animal it names. “Cope” is from the Greek word for “oar” and “pod” is Greek for foot. So a copepod is literally an Oar-Foot.
Copepods are tiny, usually transparent, crustaceans with oar-like antennae. They live in wet places: oceans, lakes, rivers, streams, swamps, bogs, and even in the water in caves. They are very small, often microscopic, and very numerous. There are 13,000 known species. The vast majority live in the ocean.
And, yes, they are small, typically only 1-2 millimeters long (0.04 to 0.08 inches). Living at the bottom of the animal food chain, they ultimately support creatures as big as whales and are the primary food source of the bird who spawned this thread.
In the Arctic, copepods are especially plentiful in polynyas, which is why the bird is fond of polynyas.
Some polynyas are permanent, others are seasonal. Off the coast of Canada, the North Water Polynya opens every spring between Ellesmere Island and Greenland. When it does, new sunlight entering the water causes a microalgae bloom, the copepods swarm to eat it, and our mystery bird arrives to eat the copepods.
But more about him later.
(copepod photo by Ume Kils on Wikimedia Commons. Click on the image to see the original)