The black-necked stork (Ephippiorhynchus asiaticus) is a tall long-necked wading bird in the stork family. It is a resident species across the Indian Subcontinent and Southeast Asia with a disjunct population in Australia. It lives in wetland habitats and near fields of certain crops such as rice and wheat where it forages for a wide range of animal prey. Adult birds of both sexes have a heavy bill and are patterned in white and irridescent blacks, but the sexes differ in the colour of the iris with females sporting yellow irises and males having dark-coloured irises. In Australia, it is sometimes called a jabiru although that name refers to a stork species found in the Americas. It is one of the few storks that are strongly territorial when feeding and breeding.
The black-necked stork is a large bird, 129–150 cm tall having a 230-cm wingspan. The only published weight for this species was a single specimen at 4,100 g, but this is nearly 35% less than the mean body mass of the closely related and similar sized saddle-billed stork. Therefore, this specimen of black-necked stork could have been at the low end of sizes attainable or perhaps somewhat malnourished. The plumage patterns are conspicuous with younger birds differing from adults. Adults have a glossy bluish-black iridescent head, neck, secondary flight feathers and tail; a coppery-brown crown; a bright white back and belly; bill black with a slightly concave upper edge; and bright red legs. The sexes are identical but the adult female has a yellow iris while the adult male has it brown. Juveniles younger than six months have a brownish iris; a distinctly smaller and straighter beak; a fluffy appearance; brown head, neck, upper back, wings and tail; a white belly; and dark legs. Juveniles older than six months have a mottled appearance especially on the head and neck where the iridescence is partly developed; dark-brown outer primaries; white inner primaries that forms a shoulder patch when the wings are closed; a heavy beak identical in size to adults but still straighter; and dark to pale-pink legs. Like most storks, the black-necked stork flies with the neck outstretched, not retracted like a heron. In flight it appears spindly and a black bar running through the white wings (the somewhat similar looking migratory black stork has an all black wing) with black neck and tail make it distinctive.