Long-tailed Reed Finch

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Quick Facts

  • Scientific Name: Donacospiza albifrons
  • Spanish Name: Semillero colilargo
  • Family: Thraupidae
  • Known Nicknames: Long-tailed Reed-finch, White-browed Reed Finch
  • Average Length: 13–15 cm / 5.1–5.9 in
  • Average Weight: 12–18 g / 0.42–0.63 oz
  • Wingspan: 18–22 cm / 7.1–8.7 in
  • Key Feature: Long, graduated tail and a white eyebrow stripe
  • Primary Diet: Primarily Granivore and Insectivore
  • Range: Eastern and southern Brazil, Paraguay, Uruguay, and northeastern Argentina
  • Habitat: Marshes, reed beds, and wet grasslands with tall grass or sedges
  • Social Structure: Solitary or in Pairs
  • Nesting/Breeding: Cup-shaped nest built in dense reeds or grass tussocks
  • Conservation Status: Least Concern (LC)
  • Population Trend: Stable

The Long-tailed Reed Finch (*Donacospiza albifrons*) is a distinctive South American songbird, most notable for its exceptionally long, graduated tail that can exceed its body length, giving it a graceful, almost elongated silhouette as it flits through dense reeds and marsh grasses. Its general appearance is subtly elegant: the male features a warm brown back, a pale whitish throat and breast, and a striking white eyebrow stripe that contrasts with its darker crown, while the female is slightly duller. A unique special feature is its strongly curved, finch-like bill, perfectly adapted for extracting seeds from tough grass stems, and its habitat specialization—it is almost exclusively found in humid, reed-filled wetlands of Argentina, Uruguay, and southern Brazil, where its cryptic coloring and skulking behavior make it a challenging but rewarding sight for birdwatchers.

Fun Facts

Despite its name, the Long-tailed Reed Finch is not a true finch but a member of the tanager family, a quirky taxonomic twist. It has a peculiar habit of rhythmically pumping its long tail up and down while foraging, almost like a metronome, which helps flush insects from dense reeds. A unique adaptation is its strongly curved, sharp claws that allow it to grip vertical reed stems and even hang upside-down like a tiny acrobat, a skill rare among seed-eating birds. Males perform a bizarre "butterfly flight" during courtship, fluttering slowly with exaggerated wingbeats while singing, a display that looks comically out of place in their marshland home.

Habitats & Distribution

The Long-tailed Reed Finch inhabits dense, tall grassy vegetation, typically near water sources such as marshes, riverbanks, and wet meadows. It is strongly associated with stands of pampas grass and reeds in open or semi-open landscapes, avoiding dense forests. Its geographical range is restricted to southern South America, occurring primarily in central and eastern Argentina, Uruguay, and southern Brazil, with isolated populations extending into Paraguay and Bolivia. Within this region, it is found from sea level up to around 1,000 meters in elevation, favoring temperate and subtropical lowland zones.

Behaviours & Reproduction

The Long-tailed Reed Finch is generally monogamous, with pairs forming during the breeding season that typically aligns with the austral spring and summer. They are usually found in isolated pairs or small family groups, defending a small territory within dense marsh vegetation. The male performs a simple courtship display, singing from exposed perches and occasionally chasing the female in a fluttering flight. Nest construction is a shared effort, building a deep, cup-shaped structure woven from grasses and reeds, suspended between vertical stems. Clutches are small, usually two to three eggs, which are incubated primarily by the female while the male guards the territory and provides food. A notable reproductive strategy is their reliance on dense, aquatic vegetation for nesting, which reduces predation risk, and they may raise two broods in a single season if conditions are favorable. Both parents feed the chicks, which fledge after about two weeks.

Diet

The Long-tailed Reed Finch (Donacospiza albifrons) is primarily granivorous, with its diet consisting almost entirely of grass seeds, particularly those from native grasses found in its marshy and reed-bed habitats. An interesting fact about its feeding behavior is that it forages both on the ground and by clambering among the stems of tall reeds and sedges, where it uses its strong, conical bill to husk seeds with remarkable efficiency. Unlike many finches that rely heavily on insects during the breeding season, this species maintains a largely seed-based diet year-round, though it will occasionally supplement with small arthropods when feeding nestlings. Another notable detail is that it often feeds in small, loose flocks outside of the breeding season, and its preference for specific grass species makes it highly dependent on the seasonal availability of seed heads, which can drive local movements in response to rainfall patterns.

Colors

The Long-tailed Reed Finch has a streaked brown and buff body, with a whitish throat and pale supercilium, while its most distinctive feature is a bright yellow shoulder patch on the wing. Its underparts are pale with fine dark streaks, and the long, graduated tail is dark brown with white outer edges. This streaked, muted coloration provides effective camouflage among reeds and grasses.

Distribution Map

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