Slaty Finch Haplospiza rustica Scientific name definitions

The Slaty Finch is found in highlands from southern Mexico to Bolivia. The distribution is fragmented and it is nowhere common, being local as it is picky with respect to habitat and food source. The Slaty Finch is found between 1,200 and 3,500 m in elevation, higher in the Andes than in Central America, and takes edge areas of humid montane forest. In particular it needs the presence of bamboo, specializing on the genus Chusquea. There are two members of this genus Haplospiza, the other is the Uniform Finch. Not unexpectedly these finches are best considered part of the tanager group but their relationship is interesting. In fact they are very closely related to two species currently considered sierra-finches (Phrygilus), the Plumbeous Sierra Finch (Geospizopsis unicolor) and Ash-breasted Sierra Finch (Geospizopsis plebejus); in turn these are all related to Catamenia seedeaters! As we find out more about the relationships of many of the finch like birds of the Neotropics we are finding that finch like bills, and also specialization on bamboo has occurred independently in various groups.

12.5 cm; average 15.5 g. A slim finch with long, pointed bill and proportionately long, yet rounded, wing. Male nominate race is mostly plain lead-gray, paler on belly and vent; upperwing blackish with gray edging; tail blackish with gray edging; iris brown; bill blackish; legs dull brownish to blackish. Differs from similar Plumbeous Sierra Finch (Geospizopsis unicolor) mainly in noticeably longer bill, also some minor plumage differences. Female is dull brownish above, obscurely streaked, wing and tail dusky with brown edging throughout, off-white with yellowish tint below, olive-streaked on breast; bill dusky, distinguished from similar female of Blue-black Grassquit (Volatinia jacarina) by larger size, longer and more triangular bill, and more thickset body. Immature male is similar to adult, but wings have brown cast and upperwing coverts edged brownish. Subspecies differ subtly in darkness of plumage and in bill structure: arcanus is distinctly darker, more blackish above, than nominate; uniformis has thicker and wider bill than others.

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Middle American subspecies uniformis, larger-billed than Neotropical ones, may deserve study to assess possibility that it represents a distinct species. Proposed subspecies barrilesensis, described from western Panama (Barilles, in Chiriquí) on basis of purportedly smaller size than uniformis, is treated as a synonym of latter, as supposed differences based on very small samples. Three subspecies recognized.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Humid highland-forest edge where Chusquea bamboo present. A Chusquea specialist. Also forages in open grassy areas adjacent to highland forest. At 1,200–3,000 in Mexico and Central America; 1,500–3,500 m in Andes.

Irruptive, with local concentrations when Chusquea bamboo flowers and seeds; no detailed information on movements.

Seeds. Forages for bamboo seeds in undergrowth, on ground or near ground; at other times may forage for grass seeds in open areas at edge of forest. During non-breeding periods forms small flocks of up to 20 individuals.

Song, from perch, sometimes in flight (then shorter and less complex), high-pitched and sputtering in nature, aptly described as sizzling. Shorter song 1–2 seconds long, a quick series of high-pitched trills and buzzes, ti-ti-ti tswee-tswotit-dzzzz, sometimes reminiscent of song of Bananaquit (Coereba flaveola). Longer songs more than 3 seconds in duration, quicker and jumbled in nature. Northern subspecies (uniformis) gives much more insect-like song dominated by high-pitched buzz, tzzzzzzz-sitis-tzzz or tzi-tzeeeeeeeeee. In one study involving ten males in Costa Rica, three song types identified; songs differed in length, also in type of sibilant note incorporated in the trill and where in trill it was inserted; a more complex and longer flight song was also identified. Call a high tseep.

Little known. Season entirely dependent on the seeding of bamboo, which appears to be seemingly random in timing; egg dates April in Costa Rica and Sept in Ecuador. Nest globular with side entrance in Costa Rica, more open-topped in Ecuador (sample too small to determine if this a genuine geographical difference); one nest was placed 1.5 m above ground on fern-festooned bank next to a mule trail, contained 3 or 4 unspotted white eggs. No other information.

Not globally threatened. Generally uncommon to rare throughout its wide range, but becomes locally common where bamboo is seeding en masse. This species’ irruptive behaviour, coupled with its preferred highland habitat, makes it very difficult adequately to assess populations, and in particular if its numbers have declined owing to the cutting of montane forests. As its needs are so specific, and as an adequate supply of seeding bamboo is possible only with huge tracts holding bamboo within them, this species would appear to be susceptible to population declines from even patchy and local habitat loss.

Alvaro began birding as an 11 year old in Canada, and eventually trained in Evolutionary Ecology studying, creatures as varied as leaf-cutter ants and Argentine cowbirds. But his career has been focused on birding tourism, both as a guide and owner of his tour company, as well as a avitourism consultant to various organizations. He is the author of Birds of Chile, New World Blackbirds: The Icterids, as well as the ABA Field Guide to the birds of California. He lives in Half Moon Bay, California where he is known for his pelagic birding trips. Email: alvaro@alvarosadventures.com.