Sombre Hummingbird

The Sombre Hummingbird is of medium size compared to other hummingbirds, measuring approximately 11-12 cm in length with a wingspan of around 17 cm. Its name aptly describes its appearance: the plumage is primarily dark green with a subtle gloss, appearing almost black under certain lighting conditions. This coloration provides effective camouflage against the forest backdrop. The underparts are slightly lighter, with a hint of grayish-green. Juvenile Sombre Hummingbirds resemble the adults but are generally duller, lacking the sheen of mature plumage. In terms of sexual dimorphism, males and females are quite similar, though females may appear marginally smaller. Confusion with similar species, such as the Swallow-tailed Hummingbird, can occur due to overlapping ranges, but the Sombre Hummingbird's more uniform coloring and lack of a forked tail are distinguishing features. When in flight, the Sombre Hummingbird exhibits a rapid, direct movement with frequent pauses to hover, a classic hummingbird trait. It perches with an upright posture, often on slender branches, enabling it to survey its territory effectively.

The diet of the Sombre Hummingbird primarily consists of nectar, which it extracts from a variety of flowering plants native to the Atlantic Forest. This hummingbird exhibits a preference for tubular flowers that produce copious amounts of nectar, such as those from the Heliconia and Costus genera. Its long, specialized bill and extendable tongue allow for efficient nectar extraction. In addition to nectar, the Sombre Hummingbird supplements its diet with small insects and spiders, crucial for protein intake. Foraging occurs throughout the day, with peaks in activity during early morning and late afternoon when flower nectar production is at its highest. This bird employs a hovering flight technique to feed, enabling it to access flowers suspended in mid-air, as well as those attached to branches and vines. Seasonal variations in diet are minimal due to the consistent availability of floral resources in its habitat.

Sombre Hummingbirds exhibit a predominantly solitary lifestyle, although they may be seen in loose aggregations when feeding at abundant floral sites. Territorial behavior is prominent, particularly during the breeding season, when males aggressively defend feeding territories from intruders. Courtship displays include aerial chases and vocalizations, with males performing rapid, darting flights to attract females. These birds are primarily diurnal, with peak activity periods in the early morning and late afternoon. Their response to predators includes swift evasive maneuvers and alarm calls, alerting nearby individuals of potential threats. Despite their small size, Sombre Hummingbirds are bold, often confronting larger birds that encroach on their territory. They do not form flocks, but may tolerate the presence of conspecifics in areas of high flower density.

The Sombre Hummingbird constructs delicate cup-shaped nests using plant fibers, spider silk, and lichens, camouflaging them against tree branches. These nests are typically situated 1.5 to 4 meters above ground in sheltered locations within the forest. The female is solely responsible for nest building, incubation, and feeding of the young. She lays a clutch of two white eggs, which she incubates for approximately 15 to 18 days. After hatching, the chicks are altricial, requiring extensive care before fledging. The fledging period lasts about 20 to 25 days, during which the female provides all necessary nourishment. The Sombre Hummingbird usually raises one to two broods per year, depending on food availability and environmental conditions.

The Sombre Hummingbird's vocalizations are not as melodious as those of some other hummingbird species. Its primary song consists of a series of rapid, high-pitched chips, repeated in quick succession. These sounds serve both as contact calls and as a means of establishing territory. Alarm calls are sharper and more insistent, often used to warn of potential predators. While not known for a dawn chorus, the Sombre Hummingbird is most vocally active during early morning and late afternoon when engaging in territorial disputes or courtship. The calls can be likened to the sound of a rapidly clicking pen, providing an auditory cue to its presence.

• 1The Sombre Hummingbird can beat its wings up to 80 times per second, enabling it to hover effortlessly while feeding.
• 2Despite their small size, Sombre Hummingbirds can fly at speeds exceeding 50 km/h, making them agile and elusive.
• 3A Sombre Hummingbird's heart can beat over 1,200 times per minute during flight, reflecting its high-energy lifestyle.
• 4This species has a unique ability to enter torpor, a state of reduced metabolic rate, to conserve energy during cold nights.
• 5Sombre Hummingbirds are known to visit over 1,500 flowers in a single day, highlighting their role as essential pollinators.
• 6Unlike many bird species, Sombre Hummingbirds do not migrate but remain within the protective cover of the Atlantic Forest year-round.
• 7Their nests are small, measuring just about 5 cm in diameter, yet provide a secure environment for their young.

The Sombre Hummingbird is currently listed as Least Concern by the IUCN, with population trends considered stable. While its habitat, the Atlantic Forest, faces significant threats from deforestation and habitat fragmentation, the Sombre Hummingbird has shown some resilience by adapting to secondary growth areas. Conservation efforts targeting the broader Atlantic Forest ecosystem indirectly benefit this species, with initiatives focusing on reforestation and the establishment of protected areas. Historical population changes are not well documented, but the bird's adaptability to altered habitats suggests some level of resilience to environmental pressures.