Sunbitterns range from 18 to 21 inches (46 to 53 centimeters) in length and 6.3 to 7.8 ounces (180 to 220 grams) in weight. They have long, slender necks and black heads with two extended white stripes above and below the eyes. The eyes are red in color. Their bills are long and straight. The upper part of the bill is black in color, while the lower bill is bright orange. Sunbitterns have orange legs. When they have their wings open, a bright sunburstlike pattern of black, yellow, and red markings appears. These are actually intended to frighten away potential predators. Sunbitterns also have long, broad fan-shaped tails marked with striking chestnut and black stripes. When the wings and tail are folded, the bright colors are concealed and the sunbittern blends in well with its environment, being either brown or chestnut-colored with black bars on the back, and paler on the neck and belly. Male and female sunbitterns tend to be fairly similar in appearance, though males are sometimes more brightly colored.
Sunbitterns are found in the New World tropics in Central America and South America. They occupy most of the southern part of Central America south to western Ecuador, and South America east of the Andes Mountains through the Amazonian portions of Colombia, Venezuela, and Guineas, as well as portions of Brazil, Ecuador, and Peru.
Sunbitterns prefer forested habitats near permanent water sources. These include fast-flowing mountain streams, slow-flowing rivers, pond areas, and swamps. Sunbitterns are generally found at altitudes between 300 and 4,000 feet (100 to 1,200 meters) although they have been seen at higher elevations as well.
Sunbitterns have a diverse diet including vertebrates, animals with backbones, such as small fish, tadpoles, eels, and frogs, as well as smaller animals such as spiders, flies, water beetles, cockroaches, katydids, dragonfly larvae, shrimp, crabs, earthworms, and moths. Sunbitterns hunt by walking slowly, looking for and following prey carefully with their necks pulled back, then quickly jabbing and spearing with their long bills. Much of the hunting is done in shallow water, although sunbitterns also forage along the forest floor. Sunbitterns have the unusual habit of washing their food before eating, particularly when they are feeding their young.
BEHAVIOR AND REPRODUCTION
Sunbitterns are often solitary, that is, they frequently live alone. However, they are sometimes found in pairs, usually male and female breeding partners. Sunbitterns are not particularly shy, but will fly to the low branches of trees if they are disturbed. Sunbitterns do not migrate, but stay generally in the same place throughout the year. However, individuals who live in dry areas may move short distances in order to find appropriate habitat.
Sunbitterns are known for their defensive posture, which they use to frighten away potential predators. The defensive posture involves opening the wings and rotating them forward to reveal the sunburst pattern, and raising and fanning the tail at the same time. This causes the sunbittern to appear to be a large and alarmingly colored bird. In order to protect a nest and chicks, adult sunbitterns will also perform a “broken-wing” display in which one wing is dragged along the ground as if broken. By drawing attention to what appears to be a helpless adult, sunbitterns are able to distract attention from the more vulnerable nest.
The sunbittern song is a high, ringing whistle and is sung most often in the morning. Sunbitterns also have an alarm call that is used to warn others of danger.
Breeding in sunbitterns occurs during the rainy season. Courtship involves calls and singing duets as well as flight displays, head bobbing displays, preening, and begging displays. Both males and females participate in nest-building. The nest is usually built on a horizontal branch 3 to 23 feet (1 to 7 meters) above the ground and consists of a large bowl of decaying leaves, mud, and other plant material. More rarely, nests are built directly on the ground. The nest is usually placed under the cover of vegetation and close to water. The female lays two or three eggs at a time. These are pink in color, often with purplish-brown spots, and hatch after twenty-seven to thirty days. Chicks hatch already covered with down, fine fluffy feathers, and with their eyes open. One chick often hatches one or two days before the other. Both males and females incubate, or sit on, the eggs, and both help feed and take care of the chicks once they hatch. Chicks are able to stand and flap their wings a week after birth, and leave the nest after approximately thirty days.
SUNBITTERNS AND PEOPLE
Because sunbitterns are exceptionally good at catching flies and spiders, sunbittern chicks are sometimes taken from their nests and raised as pets. The birds are also hunted occasionally.
The sunbittern is not considered threatened at this time. However, their populations are declining in many parts of their range due to habitat damage and destruction.