<trp-post-container data-trp-post-id='360597'>Chaco Eagle

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En bref

  • Scientific Name: Buteogallus coronatus
  • Spanish Name: Águila del Chaco
  • Famille : Accipitridae
  • Known Nicknames: Crowned Solitary Eagle, Crowned Eagle
  • Average Length: 73–79 cm / 29–31 in
  • Average Weight: 2.7–3.5 kg / 6.0–7.7 lb
  • Wingspan: 170–190 cm / 67–75 in
  • Key Feature: Prominent black crest and greyish-brown body with a white-tipped tail
  • Régime alimentaire principal : Carnivore
  • Range: Central South America (Brazil, Bolivia, Paraguay, Argentina, Uruguay)
  • Habitat: Open to semi-open dry forests, savannas, and grasslands with scattered trees
  • Structure sociale : Solitaires ou en couples
  • Nesting/Breeding: Large stick nest in tall trees or on cliff ledges
  • Conservation Status: Endangered (EN)
  • Évolution démographique : En baisse

The Chaco Eagle (*Buteogallus coronatus*), also known as the Crowned Solitary Eagle, is a formidable and elusive raptor endemic to the dry forests and savannas of central South America. Standing up to 85 cm tall with a wingspan exceeding 1.8 meters, it is one of the largest eagles in its range, characterized by a uniform slate-gray body, broad wings, and a short, black-tipped white tail. Its most striking feature is the namesake "crown"—a prominent, shaggy crest of feathers on its nape that it can raise when alert or threatened, giving it a regal, owl-like profile. Unique among its relatives, this eagle has unusually long legs and heavily scaled tarsi, an adaptation for hunting terrestrial prey like armadillos, skunks, and snakes on the ground rather than in the air. Despite its power, the Chaco Eagle is critically endangered due to habitat loss and persecution, making every sighting a rare and precious encounter with a true ghost of the Gran Chaco.

Faits amusants

Despite its name, the Chaco Eagle is not a true eagle but a large hawk, and it has a peculiar habit of swallowing its prey—often armadillos, skunks, or large snakes—almost entirely headfirst, using its powerful beak to crush bones. It exhibits unusual social behavior for a raptor, with juveniles often staying with their parents for over a year to help defend the territory and even assist in feeding younger siblings. One of its most striking adaptations is its massive, heavy-duty feet and talons, which are proportionally larger than those of many true eagles, allowing it to punch through the armored shells of armadillos with a single blow.

Habitats et répartition

The Chaco Eagle inhabits a mosaic of dry and semi-arid environments, primarily within the Gran Chaco ecoregion, which includes thorny scrublands, dry forests, and savannas with scattered palms. It also occurs in adjacent open woodlands, gallery forests along rivers, and occasionally in more humid areas like the Pantanal wetlands. Its geographical range is restricted to central South America, encompassing eastern Bolivia, western Paraguay, northern Argentina, and marginally into southwestern Brazil and Uruguay, though its distribution is highly fragmented and populations are declining due to habitat loss.

Comportements & Reproduction

The Chaco Eagle is typically solitary or found in mated pairs, maintaining large territories that they defend year-round. Their social structure is monogamous, with pairs forming long-term bonds that may last for multiple breeding seasons. Mating involves aerial displays where both birds soar in tight circles, sometimes locking talons and tumbling through the air. Nesting occurs in the austral spring, with pairs constructing large stick platforms high in trees or on cliff ledges. A unique reproductive strategy is their extremely low reproductive rate: females lay a single egg per breeding attempt, and if the chick survives, the pair may not breed again for two to three years, investing heavily in prolonged parental care that lasts up to 18 months. This slow life history makes them highly vulnerable to habitat loss and persecution.

Alimentation

The Chaco Eagle is an apex predator with a specialized diet consisting primarily of medium-sized mammals, with a strong preference for armadillos, which can make up over 50% of its recorded prey. It also hunts large rodents like agoutis and pacas, as well as skunks, opossums, and young foxes. Interestingly, this eagle is known to regularly consume tortoises and large snakes, such as boas and rattlesnakes, crushing their shells or skulls with its powerful beak. It rarely scavenges, preferring to hunt from a perch or by soaring low over the dry forests and savannas of South America, and it has been observed caching excess food in trees to eat later.

Couleurs

The Chaco Eagle is mostly dark brownish-black overall, with a distinctive pale grayish-white band across the tail and a white or buffy terminal band. Its most unique marking is the prominent, shaggy, dark crest on the crown, which it can raise and lower. Adults have a pale grayish cere and facial skin, while juveniles are mottled with brown and buff, providing camouflage in open, arid woodlands.

Distribution Map

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