Blackcapped donacobius

Donacobius atricapillus

TAXONOMY

Turdus atricapilla Linnaeus, 1766, location in error, actually eastern Brazil.

OTHER COMMON NAMES

English: Black-capped mockingthrush; French: Troglodyte a miroirs; German: Rohrspottdrossel; Spanish: Paraulata de Agua, Donacobio.

PHYSICAL CHARACTERISTICS

8.5-9 in (21-22 cm); 1.1-1.5 oz (31-42 g). Unique and unmistakable. Crown, nape, and shoulders are glossy black; back is browner; rump is olive-brown. Tail feathers are black with conspicuous white tips. Wings are blackish with conspicuous

white flash at the base of primaries. Underparts warm yellow buff with black bars on flanks. Eyes are bright yellow; legs are dusky green. Has a distendable yellow cheek pouch.

DISTRIBUTION

Panama (Darien) through lowland South America east of the Andes to coastal Brazil and northern Argentina

HABITAT

Brushy vegetation over slow-moving rivers and ponds; occurs at sea level to rarely 2,000 ft (750 m), usually lower.

BEHAVIOR

Demonstrative and noisy. Pairs indulge in loud ritualized displays, advertising the white wing-flashes and tail edgings by spreading the wings and tail. Song is a series of loud whistles. Both sexes sing in antiphonal style. Female song has a lower, grating quality not found in the male's contribution. Other members of a nesting group may also join in. The bird is territorial, with the territories often being linear along a marsh edge.

FEEDING ECOLOGY AND DIET

Not known.

REPRODUCTIVE BIOLOGY

A cooperative breeder; a nesting pair may have up to two additional helpers, which are usually young from the previous year or two. Pairs with no assistants rear only one young bird, while helpers can increase the number to two young. Nest is an open cup, usually built over or near water. Eggs usually number two in Venezuela, in Brazil frequently three. They are purplish white, covered with reddish or purplish spots and blotches. Incubation is by the female alone for 16-18 days; young are fed by both parents and by helpers, fledging at 17-18 days. Single-brooded. Adults keep young in nest cool by soaking their body feathers in water and wetting the nestlings.

CONSERVATION STATUS

Not threatened. Common or abundant over much of its range. Although marsh-drainage may destroy habitat, the species will colonize suitable vegetation arising around artificial water impoundments.

SIGNIFICANCE TO HUMANS

For two hundred years has provided much diversion and entertainment for taxonomic ornithologists, a process that will doubtless continue. ♦

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