Sandhill cranes migrate north in the spring from their wintering grounds, located in Texas, eastern New Mexico, northern Mexico, and occasionally from southeastern Arizona. The migration path they use is known as the Central Flyway, in which south-central Nebraska’s Platte River Valley is the pinch in its hourglass shape. This small area is known for its critical habitat needed for sandhill crane survival.
Each spring, between late February and mid-April, about 500,000 sandhill cranes arrive to the Platte River Valley to utilize its abundant resources. This stretch of the central Platte is one of the most important staging areas in North America for millions of migrating waterfowl, including about 80 percent of the world’s population of sandhill cranes.
Sandhill cranes fly approximately 300 to 500 miles a day, and some migrate a total of more than 10,000 miles annually. They use the 80-mile section of the central Platte to rest and refuel before they continue their journey north to breeding grounds in the Canadian Arctic, western Alaska, and northeastern Siberia. Cranes roost in the shallow, wide river channel from dusk till dawn for up to six weeks. After their night of rest, flocks disperse to adjacent cornfields and wet meadows to refuel during the day.
Sandhill cranes spend half of their day in cropfields, where they forage leftover grain from the previous fall’s harvest. Leftover grains, primarily corn, provide 80-90 percent of the crane diet. It is metabolized quickly and builds fat reserves needed for their long journey and survival. Cranes spend the other half of the day in wet meadows or grasslands, such as Mormon Island, to foraging the other 10-20 percent of their diet. Snails, grubs, earthworms, amphibians, and small reptiles provide the cranes with protein and calcium, which are critical once they arrive to breeding grounds to ensure healthy eggshells and chicks at the nest.
Wet meadows and grasslands are typically hydrologically connected to the river, so they are important courtship, loafing, and bathing areas. They are diverse and secluded, where cranes can roost at times when the river is unsuitable. Managing the resilience of habitats like Mormon Island is crucial for species diversity and sandhill crane survival.