White Ibis

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. Among standard measurements, American White Ibis measure 20.5–31 cm (8.1–12 in) along each wing, have a tail measurement of 9.3–12.2 cm (3.7–4.8 in), a tarsus of 6.75–11.3 cm (2.66–4.4 in) and a culmen of 11–16.9 cm (4.3–6.7 in).