The whooping crane (Grus americana) is the tallest North American bird, named for its whooping sound. It is an endangered crane species. Along with the sandhill crane (Antigone canadensis), it is one of only two crane species native to North America. The whooping crane's lifespan is estimated to be 22 to 24 years in the wild. After being pushed to the brink of extinction by unregulated hunting and loss of habitat to just 21 wild and two captive whooping cranes by 1941, conservation efforts have led to a limited recovery. The total number of cranes in the surviving migratory population, plus three reintroduced flocks and in captivity, now exceeds 800 birds.