Medium Tree Finch (Camarhynchus pauper) — Vorstman's Guide to the Birds of the Andes and West Coast

Voice

The song is a series of a few repeated whistled notes, similar to that of the other tree finches. The call is a short, high chirp.

Listen: CallXC816055

Recording: Barry Edmonston — CC BY-NC-SA 4.0 · xeno-canto

Identification

12–13 cm, with a thick, curved bill intermediate in size between those of Large and Small Tree Finches. Adult males have a black head and throat and a blackish upper breast; in younger males the black is more restricted. The upperparts are olive-grey, the underparts dingy white to greyish buff, with faint streaking on the flanks. Females and young birds lack the black and have a paler bill.

Confusion species

Small Tree Finch Camarhynchus parvulus is smaller, with a clearly smaller, shorter bill. Large Tree Finch Camarhynchus psittacula is slightly larger, with a heavier bill; it is scarce on Floreana. Hybrids with Small Tree Finch cannot be reliably identified in the field. Ground finches (Geospiza) have a conical bill with a straight upper edge.

Habitat

The humid highlands of Floreana, in remnants of Scalesia forest, woodland with Zanthoxylum and other native trees, and scrub; above about 300 m. It searches trees for insects and larvae in bark and twigs, and also eats fruit and buds. The nest is a domed structure in a tree.

Where the bird is most at home, classified by the vegetation units of the Andes and the west coast.

Range and movements

Endemic to Floreana (Galápagos); it occurs on no other island. Absent from mainland Colombia, Ecuador, Peru and Bolivia.

Resident

A map of the archipelago itself: on the main map this bird would be a speck at the edge, and with island birds the question is exactly which islands it holds. The islands where it is absent are shown in grey. Island by island distribution follows the standard references; island outlines: Natural Earth (public domain).

How and when to look

In the highlands of Floreana, around Cerro Pajas and Asilo de la Paz, where it forages in the canopy with the other tree finches.

Conservation status

Critically Endangered. Its habitat is very small and largely degraded by farming and introduced plants. The larvae of the introduced parasitic fly Philornis downsi kill a large share of the nestlings; introduced rats and cats are also a threat. A large restoration programme on Floreana includes the removal of introduced mammals.

Scientific name

Camarhynchus pauper | Ridgway, 1890

Ridgway described the species in 1890 and placed it straight away in the genus where it still stands. The genus Camarhynchus was introduced in 1837 by Gould. The genus name combines Ancient Greek kamara, 'arch' or 'vault', and rhunkhos, 'bill'. The species name is Latin pauper, 'poor' or 'meagre'. The specimen the first description was based on came from Floreana Island, Galápagos.