" They have been here for two hundred million years,” he says, “and until recently there were ten thousand species. They evolved to go in search of food, traveling farther than any other animal to survive, and thus they colonized the earth. From the oilbird, which lived in pitch-black caves, to the bar-headed goose, which bred only on the desolate Tibetan plateau. From the rufous hummingbird, which survived in the freezing altitude of fourteen thousand feet to the Rüppell’s griffon vulture, which could fly as high as a commercial airplane. These extraordinary creatures were undoubtedly the most successful on earth, because they courageously learned to exist anywhere. "

― Charlotte McConaghy , Migrations