American White Ibis

Description:

American White Ibis (Eudocimus albus) in breeding plumage at Green Cay Wetlands, Boynton Beach, Florida. << The white plumage and pink facial skin of adult American White Ibises are distinctive. Adults have black wingtips that are usually only visible in flight. In non-breeding condition the long downcurved bill and long legs are bright red-orange. During the first ten days of the breeding season, the skin darkens to a deep pink on the bill and an almost purple-tinted red on the legs. It then fades to a paler pink, and the tip of the bill becomes blackish. >>

Habitat:

The American White Ibis (Eudocimus albus) is a species of bird in the ibis family Threskiornithidae. It is found from the mid-Atlantic and Gulf Coast of the United States south through most of the New World tropics. This ibis is a medium-sized bird with an overall white plumage, bright red-orange down-curved bill and long legs, and black wing tips that are usually only visible in flight. Males are larger and have longer bills than females. The breeding range runs along the Gulf and Atlantic Coast, and the coasts of Mexico and Central America. Outside the breeding period, the range extends further inland in North America and also includes the Caribbean. It is also found along the northwestern South American coastline in Colombia and Venezuela. Populations in central Venezuela overlap and interbreed with the Scarlet Ibis. The two have been classified by some authorities as a single species. The diet consists primarily of small aquatic prey such as insects and small fishes. Crayfish are its preferred food in most regions; however, it can adjust its diet according to the habitat and prey abundance. It is a tactile non-visual forager, whose main foraging behavior is probing with its beak at the bottom of shallow water to feel for and to capture its prey. During the breeding season, the American White Ibis gathers in huge colonies near water. Pairs are predominantly monogamous and both parents care for the young, although males tend to engage in extra-pair copulation with other females to increase their reproductive success. Males have also been found to pirate food from unmated females and juveniles during the breeding season. The white plumage and pink facial skin of adult American White Ibises are distinctive. Adults have black wingtips that are usually only visible in flight. In non-breeding condition the long downcurved bill and long legs are bright red-orange. During the first ten days of the breeding season, the skin darkens to a deep pink on the bill and an almost purple-tinted red on the legs. It then fades to a paler pink, and the tip of the bill becomes blackish. It is difficult to determine the sex of an adult American White Ibis from its external appearance, since the sexes have similar plumage. However, there is sexual dimorphism in size and proportion as males are significantly larger and heavier than females and have longer and stouter bills. A study of the American White Ibis in southern Florida yielded weight ranges of 872.9 to 1,261 g (1.924 to 2.78 lb) for males and 592.7 to 861.3 g (1.307 to 1.899 lb) for females, with average weights of 1,036.4 g (2.285 lb) for males and 764.5 g (1.685 lb) for females. The length of adult female and male birds ranges from 53 to 70 cm (21 to 28 in) with a 90 to 105 cm (35 to 41 in) wingspan. The newly hatched American White Ibis is covered with gray down feathers, deepening to dark brown or black on the head and wings. The chest is often bare and there can be a white tuft on the head. The irises are brown. The exposed skin is pinkish initially, apart from the tip of the bill which is dark gray, but turns gray within a few days of hatching. The bill is short and straight at birth and has an egg tooth which falls off between days five and nine, and develops three black rings from around day six, before turning gray by around six weeks of age. The gray to sandy gray brown juvenile plumage appears between weeks two and six, and face and bill become pink a few weeks later, while the legs remain gray. The irises have turned slate-gray by this stage. Once fledged, the juvenile American White Ibis has largely brown plumage and only the rump, underwing and underparts are white. The legs become light orange. As it matures, white feathers begin appearing on the back and it undergoes a gradual molt to obtain the white adult plumage. This is mostly complete by the end of the second year, although some brown feathers persist on the head and neck until the end of the third year. Juvenile birds take around two years to reach adult size and weight. Like other species of ibis, the American White Ibis flies with neck and legs outstretched, often in long loose lines or 'V' formations—a 1986 field study in North Carolina noted over 80% of adult ibis doing so, while juveniles rapidly took up the practice over the course of the summer. The resulting improvement in aerodynamics may lower energy expenditure. These lines fly in an undulating pattern as they alternately flap and glide. Soaring in a circular pattern is also seen. Heights of 500 to 1,000 m (1,600 to 3,300 ft) may be reached as birds glide over flights of 20 km (12 mi) or more. More commonly, birds fly between 60 and 100 m (200–350 ft) above the ground, gliding or flapping at a rate of around 3.3 wingbeats a second. The main call of the American White Ibis is a honking sound, transcribed as urnk, urnk, or hunk, hunk. The call is used in flight, courtship or when disturbed. Birds also utter a muted huu-huu-huu call while foraging, and make a squealing call in courtship. Young in the nest give a high-pitched zziu as a begging call. Immature American White and Scarlet Ibises are very difficult to tell apart, although Scarlet Ibises tend to have darker legs and bare skin around the face. An immature American White Ibis could be mistaken for an immature Glossy Ibis, but the latter is wholly dark brown and lacks the white belly and rump. The adult is distinguishable from the Wood Stork, which is much larger and its wings have more black on them. The American White Ibis is most common in Florida, where over 30,000 have been counted in a single breeding colony. It also occurs throughout the Caribbean, on both coasts of Mexico (from Baja California southwards) and Central America, and as far south as Columbia and Venezuela. The non-breeding range extends further inland, reaching north to Virginia, and west to eastern Texas. The species is known to wander, and has been sighted, sometimes in small flocks, in states far out of its usual range. (credit: http://en.wikipedia.org/wiki/American_Wh...)