Many other species of birds use the Central Flyway too, Volden said. Rare birds occasionally are spotted, too. One, the Eskimo Curlew, a smallish wading bird with a down-turned beak, was thought to be extinct until about 10 years ago when a naturalist spotted a group of them near the Nature Center. But later observers confirmed the presence of the Curlews. None have been seen in the last couple of years, he said, so no one knows for sure if they are still around or even exist.
Bird migration is common.
Three-quarters of the bird populations in North American migrate, some thousands of miles, others a few hundred. But how they do it remains a mystery, Volden said. Small birds like warblers tend to migrate at night to avoid predatory hawks and eagles. Experiments have shown the birds somehow use stars to guide their movements. Because cranes make multiple migrations throughout their lifetimes, it is thought they may guide themselves by learning landmarks from older birds.