The Inca tern is one eye-catching bird. It has a dark gray plumage and a brilliant red bill, legs and feet -- but the most striking feature is the bright white handlebar "moustache" of specialized feathers growing out from the fleshy yellow gape at the corners of its beak. It may look as though the moustache is nothing more than an unusual ornament shared by all members of the species, but scientists have learned that the length of an Inca tern's moustache is a reliable signal of its body condition, and that terns with longer moustaches tend to mate together and have more and larger chicks.
Inca terns nest along the west coast of South America from northern Peru to central Chile (roughly the extent of the ancient Inca Empire that gives the species its common name). This is where the cold nutrient-rich Humboldt current flows just off-shore, carrying with it swarms of small ocean fish such as anchovies. While you may enjoy eating these small fish once in a while, in a salad or on a pizza, for the Inca tern they are an essential diet staple. This means that what happens to the ocean's fish population affects Inca terns.
And what has happened over the past several decades -- overfishing by humans, mercury pollution of our oceans and other kinds of environmental damage -- unfortunately has led to a major decline in Inca terns. Once numbering in the millions, the current population estimate is just over 150,000 birds, and the species is now listed as near threatened by the International Union for the Conservation of Nature.
If you come to the National Aviary's Fins and Feathers weekend Saturday and Sunday, you will see Inca terns and others of our top fish-eaters in action, including penguins, pelicans and, of course, bald eagles. And you will learn how careful seafood choices can help save birds like the Inca tern, which depend on healthy oceans with abundant fish for their survival.