The adult is a large bird 83-115 cm (33-45 in) tall and 140-180 cm (58-71 in) in wingspan. Males typically weigh 2.5–3.3 kg (5.5-7.3 lbs); females weigh 2.0–2.8kg (4.4-6.2 lbs), although large birds are up to 4.5 kg (10 lbs). It appears all white on the ground, with blackish-gray legs and pink feet. In flight, the trailing edge of the wings is black. The head is dark brown with a bald, black face, and the thick downcurved bill is dusky yellow. Juvenile birds are a duller version of the adult, generally browner on the neck, and with a paler bill.
This is a subtropical and tropical species which breeds in much of South America, Central America and the Caribbean. The Wood Stork is the only stork that presently breeds in North America. In the United States there is a small and endangered breeding population in Florida, Georgia, and South Carolina, along with a recently discovered rookery in southeastern North Carolina. On the other hand, in Santa Catarina state (Brazil) its decline seems to have been reversed: after an absence between the late 1960s and the mid-1990s, the species is now again regularly encountered there, in particular in the Tubarão River region. It is likely that the Paraná River region's wetlands served as a stronghold of the species, from where it is now re-colonizing some of its former haunts. Globally, it is considered a Species of Least Concern by the IUCN due to its large range.
The Wood Stork is a broad-winged soaring bird that flies with its neck outstretched and legs extended. It forages usually where lowering water levels concentrate fish in open wetlands; they also frequent rice paddies. Wood storks walk slowly and steadily in shallow water up to the belly seeking prey, which, like that of most of their relatives, consists of fish, frogs and large insects. They catch fish by holding their bill open in the water until a fish is detected.
It is a resident breeder in lowland wetlands with trees. The large stick nest is built in a forest tree. They breed once a year, and 3-5 eggs are laid in the typical clutch. The eggs are incubated 27-32 days by both sexes. Their reproductive cycle is triggered when waterholes dry up sufficiently to concentrate fish in sufficient numbers for efficient feeding of the chicks.
This species seems to have evolved in tropical regions; its North American presence probably postdates the last ice age. A fossil fragment from the Touro Passo Formation found at Arroio Touro Passo (Rio Grande do Sul, Brazil) might be of the living species; it is at most of Late Pleistocene age, a few 10.000s of years. North American fossils from that time are of an extinct larger relative, M. wetmorei. This was probably a sister species; both occurred sympatrically on Cuba at the end of the Pleistocene.