The Blue-backed Fairy Bluebird is a member of the family Irenidae, which it shares with the Blue-winged, Orange-bellied, and Golden-fronted Leafbird, the Greater and Lesser Green Leafbird, and the Common, Greater, and Lesser Iora.
This charmingly-named bird lives mainly in Thailand, Bhutan, Malaysia and other Southeast Asian countries, which has earned it its other name, the Asian Fairy-bluebird. (Either spelling/hyphenation is generally accepted, and often both are used in the same context.) It can also be seen at such ornithological santuaries as the San Diego Zoo. The male is usually a medium blue on top and jet-black underneath, with strong black markings on its wings and belly; the female is blue underneath as well, but with sharp black wings.
Its scientific name is Irena puella. There is only one other bird in the genus Irena - the Singapore Fairy-bluebird. Both birds live in lowland rainforests, and live on figs and other fruit, along with the occasional insect. Fairy-bluebirds line their nests with green moss. The females build the nests, and both sexes feed the young.
Their song is reputed to be as lovely as their name: one observer wrote, "In the Panbari Forest of Kaziranga National Park, Assam, India, they sat high in the canopy of fruiting trees giving mellow liquid notes but never stayed in any spot for very long."
According to thesis work done at the National University of Singapore in 1996, "extensive clearing of forests in Singapore for development since its founding has resulted in both forest loss and fragmentation," threatening the habitat of this as well as many other regional birds.
http://www.dbs.nus.edu.sg/lab/cons-lab/new_page_1.htm describes more of the thesis work on their habitat;
http://www.montereybay.com/creagrus/fairy-bluebirds.html is one birdwatcher's description of these birds;
http://www.bird-stamps.org/species/121013.htm features stamps from all over celebrating the birds.