The Volcano Hummingbird is endemic to the Central Cordillera in Costa Rica, and to the Talamanca Cordilleras of Costa Rica and western Panama. It occupies mountaintops from 1800 meters to the highest peaks, and descends as low as 1200 meters in the non-breeding season (Stiles & Skutch 1989). Individuals have a green back but exhibit clear sexual dimorphism that varies by region: males are distinguished by bright gorget color and the amount of buffy and black below the tail, which increase with latitude (Stiles & Skutch 1989). In contrast, females lack a colored gorget, have a white breast, and are slightly larger than males (Henderson 2002); average female weight is 2.8 g while average male weight is 2.5 grams (Stiles & Skutch 198), though both are approximately 7.5 centimeters in length (Garrigues & Dean 2007). Evolutionarily, mountaintops exist as genetic islands of suitable habitat, which contribute to regional variation within the species (Ditto & Frey 2007, Garrigues & Dean 2007). At these high elevations, the Volcano Hummingbird prefers to forage in montane forest and forest edges (including páramo), overgrown open areas, and gardens (Henderson 2002). Stiles and Skutch (1989) also note a preference for secondary growth resulting from volcanic eruptions, landslides, or human disturbance. Volcano hummingbirds are nectar-feeding trapliners, meaning they visit a regular circuit of the same flowers to forage (Gill 1988). Preferred nectar sources are a variety of small, often insect-pollinated flowers including Fuchsia, Salvia, Bomarea, foxglove (Digitalis), Indian paintbrush (Castilleja), blueberry (Vaccinium) and blackberry (Rubus), and Miconia (Henderson 2002). They will also filch nectar from tubular flowers in the territory of larger hummingbirds (Hilty 1994; Fogden & Fogden 2005). The Volcano Hummingbird enters torpor at night, a period when body temperature is lowered to near ambient to conserve energy (Bucher & Chappell 1997), and has a much faster metabolism than larger species (Wolf et al. 1975); a nesting female should visit about 2700 flowers per day to account for metabolic and foraging energy costs (Hainsworth & Wolf 1972). Stiles & Skutch (1989) observe that during the breeding season (August-February), female Volcano Hummingbirds construct compact cup nests decorated with moss and lichen on the outermost branches of trees and shrubs or dangling from overhanging banks facing south or east. Males are very territorial of desirable perches and surrounding foraging area and defend them with diving displays that include loud calls and wing snapping (Fogden & Fogden 2005; Clark et al. 2011). As with other high elevation species, the Volcano Hummingbird is sensitive to climate change that pushes suitable habitats further up mountaintops (Lawler et al. 2009).
Habitat and Ecology
IUCN Red List Assessment
Red List Category
Red List Criteria
This tiny endemic bird inhabits open brushy areas, paramo, and edges of elfin forest at altitudes from 1850 m to the highest peaks. It is only 7.5 cm long. The male weighs 2.5 g and the female 2.8 g. The black bill is short and straight.
The adult male Volcano Hummingbird has bronze-green upperparts and rufous-edged black outer tail feathers. The throat is grey-purple in the Talamanca range, red in the Poas-Barva mountains and pink-purple in the Irazú-Turrialba area, the rest of the underparts being white. The female is similar, but her throat is white with dusky spots. Young birds resemble the female but have buff fringes to the upperpart plumage.
The female Volcano Hummingbird is entirely responsible for nest building and incubation. She lays two white eggs in her tiny plant-down cup nest 1–5 m high in a scrub or on a root below a south or east facing bank. Incubation takes 15–19 days, and fledging another 20-26.
The food of this species is nectar, taken from a variety of small flowers, including Salvia and Fuchsia, and species normally pollinated by insects. Like other hummingbirds it also takes some small insects as an essential source of protein. In the breeding season male Volcano Hummingbirds perch conspicuously in open areas with flowers and defend their feeding territories aggressively with diving displays. The call of this rather quiet species is a whistled teeeeuu.
- Stiles and Skutch, A guide to the birds of Costa Rica ISBN 0-8014-9600-4