Launched by the Zoological Society of London (ZSL) in January 2007, the EDGE of Existence program is a global conservation initiative that focuses on threatened species with unique evolutionary characteristics. EDGE is an acronym for Evolutionarily Distinct and Globally Endangered, which sums up some of the criteria for being included on the EDGE list. Recently scientists from the ZSL and Yale University assessed the 9,993 recorded bird species in the world and listed the top 100 according to various scientific parameters. The top ten on the list, from one to ten, includes the giant ibis (Thaumatibis gigantea); the New Caledonian owlet-nightjar (Aegotheles savesi); the California Condor (Gymnogyps californianus); the kakapo (Strigops habroptila); the kagu (Rhynochetos jubatus); Bengal florican (Houbaropsis bengalensis); the Forest owlet (Heteroglaux blewitti); the Philippine eagle (Pithecophaga jefferyi); Christmas Island frigatebird (Fregata andrewsi); and the Sumatran ground cuckoo (Carpococcyx viridis).
As the world’s largest ibis, the giant ibis measures up to 106 cm in length with an upright standing height of up to a meter and weighing 4.2 kg on average. They have long, curved beaks that they use for foraging in shallow waters and between vegetation, with their diets including aquatic invertebrates, crustaceans, small reptiles and amphibians, as well as earthworms, locusts, mole-crickets, cicadas and other insects. Their feathers are dark gray-brown in color, with silver-grey wing tips and black crossbars. Their heads are dark grey in color and devoid of feathers and their eyes are dark red. Their legs are orange and they have yellow-brown beaks. There are thought to be only 230 pairs of giant ibis left in the wild, and these are all located in northern Cambodia, although there have been unconfirmed sightings in southern Laos and in Vietnam’s Yok Don National Park. Because of their remote location, not much is known about the lifespan and breeding patterns of these giant birds, however, it is known that they nest in trees, generally away from human settlements, and the female lays two eggs which both parents tend to.
As is the case with many endangered bird species around the world, the greatest threat to the giant ibis is humans who clear the wetlands for cultivation and decimate forests for timber, while the increase in human populations results in domestic settlements encroaching on previously unoccupied land. Conflict in the region has also wreaked havoc on bird populations, and the giant ibis is hunted as a food source.
There are some ecotourism initiatives in the region which draw attention to the plight of the giant ibis, but the fact remains that it is considered critically endangered and is in need of protection to prevent it from becoming extinct. Programs such as Edge bring the plight of these endangered birds to the attention of the public, increasing their chances of becoming the focus of conservation efforts.