Black-backed Water-Tyrant

Open Bird Bucket List ↗
Black-backed Water-Tyrant

Quick Facts

  • Scientific Name: Fluvicola albiventer
  • Spanish Name: Tirano de agua dorsinegro
  • Family: Tyrannidae
  • Known Nicknames: Black-backed Water-Tyrant, White-bellied Water-Tyrant, Black-backed Water Tyrant
  • Average Length: 13–14 cm / 5.1–5.5 in
  • Average Weight: 12–16 g / 0.42–0.56 oz
  • Wingspan: N/A
  • Key Feature: Striking black upperparts contrasting with pure white underparts and a white forehead
  • Primary Diet: Insectivore (primarily aquatic insects)
  • Range: Northern and central South America, from Colombia and Venezuela to northern Argentina and Uruguay
  • Habitat: Freshwater marshes, ponds, and slow-moving rivers with emergent vegetation
  • Social Structure: Usually solitary or in pairs
  • Nesting/Breeding: Cup-shaped nest built in low vegetation near water
  • Conservation Status: Least Concern (LC)
  • Population Trend: Stable

The Black-backed Water-Tyrant (*Fluvicola albiventer*) is a striking passerine bird of South American wetlands, instantly recognizable by its crisp, high-contrast plumage: a pure white head, throat, and underparts sharply offset by a jet-black back, wings, and tail. Its most unique characteristic is its behavior as a dedicated aquatic insectivore—it flits and hovers low over water, often perching on floating vegetation or exposed branches, and snatches prey from the surface with remarkable precision. A special feature is its shallow, cup-shaped nest, which it frequently builds inside abandoned nests of other birds, such as ovenbirds, or in natural cavities near water, showcasing its opportunistic adaptability. With a slender, pointed bill and a lively, bobbing gait, this tyrant flycatcher is a dynamic and unmistakable presence across marshes, riversides, and flooded grasslands from eastern Brazil to northern Argentina.

Fun Facts

Despite its name, the Black-backed Water-Tyrant is not a tyrant in the aggressive sense; it is a shy, solitary bird that often bobs its tail up and down like a nervous metronome, a quirky behavior known as "tail-pumping" thought to flush out insects. It has a unique adaptation for its aquatic habitat: its feet are not webbed, but it skillfully walks on floating vegetation and even dives underwater to escape predators, propelling itself with its wings. Another oddity is its nest—a large, messy ball of grass and leaves with a side entrance, often built in reeds over water, which it meticulously lines with soft downy feathers plucked from its own belly.

Habitats & Distribution

The Black-backed Water-Tyrant is found in South America east of the Andes, ranging from eastern Colombia and Venezuela through the Guianas, most of Brazil, eastern Bolivia, Paraguay, and into northern Argentina and Uruguay. It inhabits freshwater wetlands, including the margins of rivers, streams, lakes, and ponds, as well as marshes, flooded grasslands, and rice paddies. It prefers open or semi-open areas with emergent vegetation, such as reeds and sedges, where it perches low over the water to hunt for insects.

Behaviours & Reproduction

The Black-backed Water-Tyrant is generally solitary or found in pairs during the breeding season, defending small territories along streams and marshes. Mating involves a simple courtship where the male performs short aerial displays and vocalizations to attract a female. They are monogamous for the breeding cycle, with both parents sharing nest construction, which is a cup made of plant fibers and placed low in vegetation near water. The female lays 2–3 eggs, and both parents incubate them for about two weeks and feed the chicks. A unique reproductive strategy is their strong site fidelity, often reusing and repairing the same nest for successive broods within a season, which reduces energy expenditure. Chicks fledge after approximately 18 days, but parents may continue to feed them for a short period while beginning a new clutch nearby.

Diet

The Black-backed Water-Tyrant (Fluvicola albiventer) is an insectivorous bird whose diet consists almost exclusively of small aquatic and semi-aquatic invertebrates. It forages primarily by making short, swift flights from a low perch over open water or muddy shorelines, snatching prey from the water's surface or from emergent vegetation. Interestingly, it often wades into shallow water to pick off insects and larvae, and it has been observed following capybaras and other large mammals to capture flushed insects. Its menu commonly includes dragonfly and damselfly larvae, water bugs, beetles, flies, and small spiders, with a notable preference for prey that is active on the water's surface film, a niche that reduces competition with other flycatchers that hunt in drier habitats.

Colors

The Black-backed Water-Tyrant has a stark, high-contrast plumage: a solid black back, crown, and tail sharply divided from a pure white face, underparts, and wing patches. Its white rump and black central tail feathers create a distinctive flash in flight. This bold black-and-white pattern provides camouflage against sunlit water reflections, while the white underside helps it blend with bright sky when viewed from below.

Distribution Map

Places linked to this species. A sighting is never guaranteed.