Which marsh bird is the tallest?

   The whooping crane (Grus americana) stands an aver­age of 5 feet, with a 7-foot wingspan. In the early 1940s, fewer than 20 whooping cranes existed; today's world population is over 300. Only one flock of 150 cranes survives ¡n the wild; they fly 2,600 miles between their winter home in Aransas National Wildlife Refuge on the Texas Gulf of Mexico and their summer home in Canada's Wood Buffalo National Park. The whooping crane is protected under the Endangered Species Act.
   Working together, the United States and Canada have bred three captive flocks to produce cranes for reintroduction into wild nonmigratory flocks. To teach captive-reared flocks migration routes, the United States Fish and Wildlife Service has trained them to follow ultralight airplanes. One group successfully flew from the Necedah National Wildlife Refuge ¡n Wisconsin to Chassahowitzka National Wildlife Refuge in Florida.