Bengal Florican (Houbaropsis bengalensis), Critically Endangered
The Bengal Florican, known by locals as "the whispering bird," has a long black head and neck, long, mostly white wings, and long yellow legs. It received it's nickname from the displays of male birds, which in mating season, struts into a clearing and ruffles it neck feathers. It jumps into the air, then drifts back to the ground, giving a deep humming call as it descends--hence "the whispering bird." It usually competes with other nearby males.
The Bengal Florican survives in areas of India and Nepal, but the largest part of its fragmented population ekes out its existence in the dry grasslands of Cambodia. With less than 1500 individuals, the Bengal Florican is listed by the IUCN as Critically Endangered, and scientists estimate that it may be extinct in Cambodia within 5 years.
The biggest threat to these birds is habitat loss. According to a recent article, "Since 2005, a rush to turn grasslands into large-scale rice farms has gobbled up one-third of the Bengal Florican's habitat in Cambodia."
A land protection program, designed to stop development of critical habitat, has been implemented with some success. The program, a collaboration between the Wildlife Conservation Society, BirdLife International, and Cambodian authorities, protects 135 square miles and has canceled several previously planned developments. Still, the Bengal Florican isn't out of danger by a long shot. Though conservationists have attempted to win villager's support, resistance remains and some areas continue to be developed.
You can donate to BirdLife International, which is working to save 189 of the world's most endangered birds, including the Bengal Florican. Or, if you can spare 20,000 British pounds a year, you can become a Species Champion, and champion the survival of the Bengal Florican.
Here's a video of the Bengal Florican--unfortunately not of the male's mating dance.