Of only fifteen species of cranes in the world, just two species occur in the western hemisphere: the sandhill crane, which is the most numerous, and the whooping crane, the rarest. Why have the two North American species experienced such different recent fates? We know that the sandhill crane is perhaps the oldest crane species on earth. Their bones have been immortalized in stone for six million years. Secondly, this crane has evolved characteristics beneficial to prairie life and has adapted to farming practices that have replaced the historic native prairies of North America.
However, the whooping crane, who is not even a close relative of the sandhill crane, is decidedly dependent on wetlands, both freshwater and coastal fringe habitats. As conversion of prairie potholes to agricultural lands progressed across the continent, habitat for whooping crane was lost and resulted, along with hunting pressure, in a significant decline for the species.