Ovenbirds: Furnariidae

Physical characteristics: Greater thornbirds are the reddest in color and among the largest in size of the ovenbirds. This species has a stout, plump, body and a long tail. They have a short, pointed bill that is slightly downcurved. The upper part of the bills is blackish and the lower part of the bill is pale gray to grayish green. They have a rufous-brown to grayish brown face with a light brown stripe over the eyes. Greater thornbirds move about cautiously, not wanting to be seen, usually alone or in pairs. (Illustration by Jonathan Higgins. Reproduced by permission.) There is a reddish chestnut crown with faint pale shaft streaks; a rufous cap on the head; and a reddish brown to olive-brown hindcrown. Wings are rufous-chestnut. They have brown backs, rufous tails and whitish bellies and throats. Their rumps are brown tinged with red and their toes are gray to olive. Sexes are similar in appearance. Juveniles lack the crown patch and have a mottled, speckled, brownish breast. Adults are 7.5 to 8.3 inches (19 to 21 centimeters) long and weigh between 1.2 to 1.8 ounces (35 and 51 grams).

Geographic range: They are found in Bolivia, central Brazil, Paraguay, northern Argentina, and, possibly, in far northern Uruguay.

Habitat: Greater thornbirds inhabit the undergrowth of humid tropical forests, thickets on the banks of waterways, woodlands and scrublands. They especially like to be near ponds and other surface waters. They are found from sea level to elevations up to 4,600 feet (1,400 meters).

Diet: Their food includes insects, ants, and other small invertebrates. They are usually found foraging on the forest floor, around dense vegetation, and near the edges of water bodies such as marshes.

Behavior and reproduction: Greater thornbirds move about cautiously, not wanting to be seen. They usually move about alone or in pairs. Their song is a long series of loud, abrupt, accelerating notes such as "chip," with a sharp call of "check check" and "chweet." Their breeding season is from October to January. They build large, bulky nests that look similar to a cylinder or cone. The birds use sticks, twigs, and branches, often thorny ones, as materials to build the nest, which often contains several chambers and has a side entrance at the lower end. The interior of the nest is usually lined with fine grasses and feathers. The nest is usually attached to an outer, drooping branch of a tree or other low vegetation. Females lay three to five eggs, but five eggs are rare. Both sexes incubate the eggs and raise the nestlings.

Greater thornbirds and people: There is no known significance between people and greater thornbirds.

Conservation status: Greater thornbirds are not threatened with extinction. They are widespread and locally abundant throughout most of their habitats. They are protected in parts of their range, such as Pantanal National Park in Brazil and Esteros del Iberá and Calilegua National Parks in Argentina. ∎