The peg-billed finch is a passerine bird endemic to the highlands of Costa Rica and western Panama. Despite its name, it is not a true finch, but now recognized as a member of the tanager family (Thraupidae), after being long placed in the Emberizidae. It is the only member of the genus Acanthidops. The scientific name commemorates the American ornithologist Spencer Fullerton Baird.
Region
Central American highlands (Costa Rica and western Panama)
Typical Environment
Found in montane cloud forests, forest edges, and secondary growth with dense bamboo (especially Chusquea) understory. It frequents clearings and road edges where bamboo is abundant. The species typically stays low to mid-understory, moving through thickets in small groups. It is locally common where suitable bamboo patches persist but patchy elsewhere.
Altitude Range
1500–3200 m
Climate Zone
Highland
Ease of Keeping
Beginner friendly: 1/5
The peg-billed finch is the sole member of the genus Acanthidops and is now placed in the tanager family (Thraupidae), not among true finches. It is specialized for foraging in highland bamboo thickets, using its short, peg-like bill to pry seeds from Chusquea bamboo. The species is resident in the highlands of Costa Rica and western Panama. Its scientific name honors American ornithologist Spencer Fullerton Baird.
Temperament
discreet and active
Flight Pattern
short rapid wingbeats, low over understory
Social Behavior
Usually seen singly, in pairs, or small family groups; occasionally joins mixed-species flocks in the understory. Nests are placed low in dense vegetation, often near or within bamboo. Likely monogamous during the breeding season with both parents attending the young.
Migratory Pattern
Resident
Song Description
A thin, high-pitched series of tseet or tsee notes, delivered from low perches within bamboo. Calls are sharp and sibilant, often given while foraging and easy to miss in windy thickets.
Plumage
Plain, slightly dull olive-brown to brownish-olive overall with paler underparts; minimal contrast and little to no wing pattern. Feathers appear smooth and close-fitting, giving a sleek, compact look.
Diet
Primarily takes seeds, especially from Chusquea bamboo, which it pries open with its specialized bill. Supplements diet with small insects and other arthropods gleaned from leaves and stems. Will also consume small berries or soft plant material when available.
Preferred Environment
Feeds within dense bamboo stands, along forest edges, and in regenerating patches with abundant understory. Often forages low, moving methodically through stalks and leaf clusters.
