Wood ibis
The Wood stork (Mycteria americana) is a large American wading bird that breeds in North America. It was formerly called the "wood ibis", though it is not an ibis. Originally described by Carl Linnaeus in 1758, this stork likely evolved in tropical regions.
The head and neck of the bird are bare of feathers and dark grey in color. The plumage is mostly white, with the exception of the tail and some of the wing feathers, which are black with a greenish-purplish sheen. The legs and feet are dark, and the flesh-colored toes are pink during the breeding season. The juvenile differs from the adult, with the former having a feathered head and a yellow bill, compared to the black adult bill. The male and the female in this species look similar.
Wood storks breed in North America, much of South America, Central America, and the Caribbean. In the United States, there are small breeding populations in Florida, Georgia, and the Carolinas. In South America, these birds are found south to northern Argentina. In South America they are resident but in North America, some populations disperse after breeding, frequently to South America. Wood storks are able to adapt to a variety of wetland habitats. They can be found in estuaries, mangrove forests, swamps, ponds, freshwater marshes, flooded farm fields, lakes, streams, and river edges.
Wood storks are gregarious birds that live in flocks and nest in large colonies. By day they usually forage in flocks when not breeding, and alone and in small groups when they are breeding. In the dry season, these birds generally forage by slowly walking forward with their bill submerged in the water while groping for food. During the wet season, Wood storks forage mainly by foot stirring, where they walk very slowly with the bill in the water while pumping the foot up and down before every step. Both these hunting methods are non-visual and because of this Wood storks require shallow water and a high density of fish to forage successfully. In the afternoon, these birds usually raise in the sky to soar on thermals. When it is warm and clear, they glide after they gain an altitude of at least 610 meters (2,000 ft) continuously flapping their wings. When it is not sufficiently warm and clear, such as in the late afternoon or on cloudy days, Wood storks alternate between flapping their wings and gliding for short periods of time. These birds are generally silent but sometimes they will make some croak or hiss like a snake.
Wood storks are carnivores (piscivores, insectivores). During the dry season, they eat mostly fish, supplemented by insects. During the wet season, on the other hand, fish make up about half the diet, crabs make up about 30%, and insects and frogs make up the rest.
Wood storks are serially monogamous and form pairs that stay together only for a single breeding season. Breeding occurs anytime between November and August and it takes about four months to complete. Wood storks nest colonially in trees that are over water or surrounded by water, with up to 25 nests in one tree. The nest itself is built by the male from sticks and green twigs collected from the colony and the surrounding area. The greenery usually starts to be added before the eggs are laid but after the main structure of the twigs is completed. This greenery functions to help insulate the nest. The female lays one clutch of 3 to 5 cream-colored eggs which are incubated for 27 to 32 days by both parents. During the first week of incubation, the parents do not go far from the colony, with the exception of the short trips to forage, drink, and collect nesting material carried out by the non-incubating bird. The chicks hatch altricial, are unable to move, and weigh an average of 62 grams (2.2 oz). They are brooded for the first week after hatching, and after that when it is raining and at night. The chicks are not left alone until at least 3 weeks of age, with one parent foraging while the other guards the nest and chicks. When the chicks are at least 3 weeks old, they are large enough to stay and protect the nest. They fledge 60 to 65 days after hatching and reach reproductive maturity at 4 years of age.
Globally, Wood storks are not considered to be endangered, however, in the United States, on the other hand, they are considered to be threatened. This is caused by habitat loss, drought, as well as predation on eggs and chicks. Hunting and egg-collecting by humans have been implicated as a factor in the decline of South American wood storks. Humans also cause nest failures through ecotourism. In both North and South America, habitat alteration has caused the Wood stork to decline, with levee and drainage systems in the Everglades causing a shift in the timing of breeding and thus a decrease in breeding success.
According to Partners in Flight resource, the total breeding population size of the Wood stork is 450,000 birds. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.