An American Indian tells about a brave who found an eagle's egg and put it into the nest of a prairie chicken. The eaglet hatched with the brood of chicks and grew up with them. All his life, the changeling eagle, thinking he was a prairie chicken, did what the prairie chickens did. He scratched in the dirt for seeds and insects to eat. He clucked and cackled. And he flew in a brief thrashing of wings and flurry of feathers no more than a few feet off the ground.
After all, that's how prairie chickens were supposed to fly. Years passed. And the changeling eagle grew very old. One day, he saw a magnificent bird far above him in the cloudless sky. Hanging with graceful majesty on the powerful wind currents, it soared with scarcely a beat of its strong golden wings. “What a beautiful bird!” said the changeling eagle to his neighbor. “What is it?” “That's an eagle–the chief of the birds,” the neighbor clucked. “But don't give it a second thought. You could never be like him.” So the changeling eagle never gave it another thought. And it died thinking it was a prairie chicken.
Ted Engstrom, The Pursuit of Excellence