The Shining Sunbeam Hummingbird (Aglaeactis cupripennis) is a species of hummingbird found in the Andes Mountains of Peru, Bolivia, Chile, and Argentina. With its vibrant iridescent plumage that shimmers in the sunlight like a beam of light, this hummingbird aptly earns its common name.
Introduction
The Shining Sunbeam is a medium-sized hummingbird, measuring around 11-12 cm in length. The male has striking plumage, with a velvety purple-black head, bright metallic green throat, chestnut-colored belly, and a deeply forked tail. However, it is the male’s back and rump which shine brilliantly with an iridescent reddish-coppery color, for which the species gets its scientific name cupripennis, meaning “coppery-winged”. When the light catches the males’ feathers just right, it results in a dazzling radiance – almost as if a sunbeam were reflecting off them.
The female Shining Sunbeam lacks the vibrant plumage of the male, instead being olive green above, grayish below, and having white markings on the tips of the outer tail feathers. Both the male and female have a slender downcurved bill adapted for reaching nectar at the base of long tubular flowers.
This hummingbird inhabits the arid, mountainous regions of the South American Andes. Here it can be found frequenting rocky ravines, canyons and gorges, mountain meadows, and scrubland – anywhere that provides its favored nectar-producing flowers.
Evolution and Taxonomy
The Shining Sunbeam belongs to the hummingbird family Trochilidae and the subfamily Trochilinae. Hummingbirds are endemic to the Americas and the Shining Sunbeam’s closest relatives are found among the “Brilliants” – a colorful group containing over 100 species. This includes the famed Giant Hummingbird and the Marvelous Spatuletail.
DNA analysis indicates that hummingbirds originated in South America 22-42 million years ago during the Oligocene period, diverging from their nearest ancestor – the swifts. Rapid hummingbird diversification took place during the Miocene period about 13 million years ago, likely influenced by the rapid uplift of the Andes mountains which created new habitats and isolating barriers that drove speciation. The Shining Sunbeam itself is thought to have originated as a distinct species around 1.5 million years ago, during the Pleistocene.
Officially, the Shining Sunbeam is classified as:
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Apodiformes
Family: Trochilidae
Genus: Aglaeactis
Species: A. cupripennis
There are two recognized subspecies:
– A. c. cupripennis found in Peru and northern Chile. This is the nominate subspecies.
– A. c. castelnaudii found in Bolivia, southern Peru, northern Chile and northwestern Argentina.
Description
As mentioned earlier, the male Shining Sunbeam has unmistakable bright, metallic plumage. The forehead and crown are a deep iridescent purple-blue. This transitions to an equally iridescent emerald green throat. The chest is a rich coppery-bronze. The belly is cinnamon-rufous. The upperparts are bronzy-golden while the undertail coverts are white. The long forked tail is also bronzy-golden with a bold white spot at the tip of each outermost feather. The wings are a mixture of bronzy-brown and purple-black.
The much duller female has gray-olive upperparts. The underparts are cinereous (gray with a brownish tinge), becoming paler on the throat and belly which are marked with obscure dark streaks. The outer tail feathers have conspicuous white tips. The central tail feathers are olive-brown with rufous-brown fringes.
Both sexes share the thin downcurved bill with a black upper mandible and a pale pinkish lower mandible. The eyes are dark brown. The legs and feet are flesh-colored.
Juveniles resemble the adult female but with buffy scalloping on the underside and rufous fringes on the upperwing coverts.
Males average 11 cm long and females are slightly smaller at 10 cm. Weights range from 5-7 grams. The wingspan is approximately 6 cm.
Habitat and Distribution
The Shining Sunbeam inhabits arid, mountainous areas of the South American Andes. Its elevational range extends from around 1,500 – 4,800 m. It generally prefers rocky slopes, gorges, open scrublands, and meadows with scattered shrubs and trees. Proximity to cliffs, ravines, or streams is beneficial as they provide sheltering niches.
This species has a relatively limited distribution confined to the Andes in southeastern Peru, western Bolivia, northern Chile, and northwesternmost Argentina.
In Peru, it is found in the departments of Puno, Tacna, Moquegua, Arequipa and Ayacucho. It inhabits slopes and valleys in the puna and paramo zones.
In Bolivia, it is found in the western and southwestern departments of La Paz, Oruro, and Potosi.
In Chile, small isolated populations exist in the northernmost part of the country in the regions of Arica-Parinacota, Tarapaca and Antofagasta.
In Argentina, it barely enters the province of Jujuy in the extreme northwest.
Diet and Feeding
Like all hummingbirds, the Shining Sunbeam subsists entirely on nectar. It uses its specialized tubular tongue to lap up the high-energy sugary nectar from flowers. It also catches small insects and spiders to obtain proteins, minerals and other nutrients lacking in its nectar diet.
Some key nectar sources include:
– Bromeliads (Puya sp., Tillandsia sp.)
– Angel’s trumpet (Brugmansia sp.)
– Fuchsia (Fuchsia sp.)
– Firebush (Trichome sp.)
– Red-hot-poker (Kniphofia sp.)
– Aloe plants (Aloe sp.)
– Tobacco plant (Nicotiana sp.)
– Lion’s tail (Leonotis sp.)
– Coral vine (Antigonon sp.)
The flowers adapted to pollination by hummingbirds are typically red, orange or pink, and are often trumpet or cone-shaped with abundant nectar at the base. The Shining Sunbeam prefers cup-shaped flowers into which it can conveniently insert its bill and access the nectar.
It feeds throughout the day, visiting hundreds of flowers each day to fuel its high metabolism. It utilizes its aerial agility to hover in front of flowers while lapping nectar at an average of 13 licks per second! It periodically pauses to perch on a lookout to survey for food sources and competitors.
Courtship and Breeding
The breeding season depends on elevation and lasts from November to April in the northern part of the range. Further south breeding takes place October to early March.
Males are promiscuous and polygynous. They seek to attract females by flying back and forth in a prolonged hovering display, orienting their iridescent feathers toward the sun to dazzle females. The males also vocalize a mix of chirps and buzzing notes during courtship displays.
Once paired, the female constructs a small cup nest out of plant down, spider webs and lichens, attaching it to a vertical rock face, tree branch or structure. Nest heights are 5-15 m above ground.
The female lays just two tiny white eggs. She incubates them alone for 16-19 days. The chicks hatch with eyes closed and almost devoid of feathers. The female cares for and feeds the chicks with regurgitated food. They fledge at around 23-30 days old.
Migration
Shining Sunbeams are resident and do not undertake any major migrations. However, they may make minor elevational movements tracking the flowering of nectar plants. For example, during the nonbreeding season they may move to somewhat lower elevations.
Longevity and Mortality
Wild Shining Sunbeams likely live 2-5 years on average based on data for related hummingbird species. The oldest known wild hummingbird is a Broad-tailed Hummingbird that was recaptured after being banded at least 7 years and 9 months earlier.
Threats and Conservation Status
Shining Sunbeams face habitat degradation from human activities like mining, residential development and introduction of non-native plants. Climate change could also alter the flowering cycles and distributions of the species’ nectar plants. Predation pressure comes from birds of prey like the Aplomado Falcon. Parasitic botflies and mites may also afflict hummingbirds.
The species has a relatively limited range and fragmented distribution. However, since it utilizes a variety of mountain habitats and flower resources, it remains fairly common throughout its range.
The Shining Sunbeam is therefore evaluated as Least Concern on the IUCN Red List of Threatened Species. The population is suspected to be decreasing but not at a rate that would warrant a threatened category. More research is needed to determine precise population sizes and trends.
Some protected areas such as Manu National Park in Peru and Lauca National Park in Chile help safeguard remaining habitat for the species. Further habitat protection and responsible ecotourism focused on the species may aid ongoing conservation efforts.
Interesting Facts
– The males’ iridescent feathers do not produce color through pigments, but instead derive their hues via the physical structure of the feathers which refract and interfere with specific wavelengths of light. The exact hue can shift depending on viewing angle.
– To conserve energy on cold nights, the Shining Sunbeam enters a state of torpor, lowering its body temperature and metabolic rate.
– The species is a common pollinator of the beautiful red passionflower (Passiflora coccinea) which shares parts of its range.
– While feeding, its wings beat up to 70 times per second and its heart rate reaches 1,260 beats per minute!
– The eggs of the Shining Sunbeam are only about 1 cm long – smaller than a jellybean!
– Like other hummingbirds, the Shining Sunbeam possesses a number of anatomical adaptations for its nectar-feeding lifestyle including a slender bill and tongue, enlarged heart muscles, and weak feet.
Summary
With its radiant plumage and energetic disposition, the aptly named Shining Sunbeam Hummingbird is a jewel of the Andean Mountains. While the dazzling males put on energetic displays and exhibit gleaming feathers, the more subtly clad females construct meticulous nests and attentively incubate the tiny eggs. This high-flying species dashes about on whirring wings seeking nectar from brilliant high-altitude flowers adapted perfectly to the hummingbirds’ needs. Although limited in range, the Shining Sunbeam remains a fairly common denizen of rocky ravines and mountain meadows. With responsible stewardship of its specialized habitat, this brilliant bird will continue to brighten the mountainsides as a living sunbeam.