The main cause of death of the whooping crane is collision with power lines during migration. Development of agricultural, recreational and industrial sites along the migrational and wintering sites have also caused the numbers of whooping cranes to decrease. Habitat loss is a danger to the whooping cranes. Major areas of concern are conversion of wetlands and grasslands, changes in agricultural land use, erosion, livestock grazing in wetland areas, increased use of pesticides and fertilizers, water diversion, urban expansion, deforestation, afforestation, marsh and shoreline erosion, pollution and oil development. The migration route, nesting locations and wintering routes are learned behaviors.
Young birds learn the route on the first migration.
Whooping cranes eat shellfish, snakes, acorns, small fish and wild fruit while they winter in Texas. They eat larval insects, snails, leeches, frogs, minnows, rodents, and berries while in Canada. During migration they may scavenge such things as dead ducks or marsh birds. Also they eat aquatic animals, roots, plants and waste grain. One management concern of whooping cranes in the Aransas National Wildlife Refuge is the danger of destroying the entire population there if an oilspill occurs.