The White-tipped Sicklebill (Eutoxeres aquila) is a fascinating hummingbird species found in Central and South America. With its long, curved bill and vibrant plumage, this medium-sized hummingbird has captured the interest of birders and researchers alike. In this article, we will explore the key features of the white-tipped sicklebill, including its taxonomy, geographic distribution, physical description, habitat, diet, behavior, reproduction and current conservation status.
Taxonomy and Phylogeny
The white-tipped sicklebill belongs to the hummingbird family Trochilidae. First described in 1847 by French ornithologist Charles Lucien Bonaparte, this species is placed in the monotypic genus Eutoxeres. Molecular studies indicate Eutoxeres is phylogenetically sister to the hermit hummingbird genus Phaethornis. Within the Trochilidae, E. aquila belongs to the subfamily Phaethornithinae, known as the hermit hummingbirds. Recent genetic analysis has confirmed its evolutionary relationship with other hook-billed tropical genera including Phaethornis, Ramphodon and Anopetia.
The white-tipped sicklebill has a wide distribution across Central America and northern South America. Its range stretches from southeastern Mexico through Guatemala, Belize, Honduras and Nicaragua. It is also found along the Caribbean coasts of Costa Rica, Panama and Colombia. In South America, its range extends into eastern Venezuela, Guyana, Suriname and French Guiana. Across this broad region, E. aquila is generally uncommon and local in distribution. It tends to inhabit humid lowland rainforests as well as foothill forests up to elevations of 1500 m.
The white-tipped sicklebill is a medium-sized hummingbird, measuring 11-12 cm long and weighing 5-8 grams. Several key features distinguish this species from other hummingbirds in its range. As its name suggests, E. aquila has a long downcurved bill that is black along the top and bright reddish-orange on the lower mandible. The tip of the bill is whitish or pale horn-colored.
The plumage of the male white-tipped sicklebill is primarily bronze-green above and pale grey below. When perched, a prominent white spot can be seen behind each eye. The throat and breast are glittering violet-blue. The undertail feathers range from rufous to bronze-green with white tips. The outer tail feathers are rufous with a black subterminal band. Females are similar but less vibrantly colored, with a paler throat, greyer breast and more rufous in the tail. Juveniles resemble adult females.
The white-tipped sicklebill most often inhabits tropical lowland rainforests, up to elevations of 1500 m. It prefers primary forest as well as the borders of clearings and rivers. This species seems to do well in lightly disturbed areas and secondary growth forests. E. aquila favors areas with a dense understory and many flowering plants. It is commonly seen visiting heliconia bushes to feed. Outside the breeding season, the white-tipped sicklebill may also be found in semi-open areas like forest edges and gardens. But it always remains close to woodland cover.
Like all hummingbirds, the white-tipped sicklebill feeds on floral nectar as its main energy source. It uses its specialized bill to drink from tubular blossoms of heliconia, ginger, banana and other plants. The curved bill allows it to access nectar from exotic flowers not used by other hummingbirds. This species tends to prefer flowers located in the lower level and understory. The sicklebill also consumes small insects such as spiders and gnats. It hawks flying insects in aerial sallies and gleans other arthropods from foliage.
Behavior and Voice
The white-tipped sicklebill is somewhat slow and deliberate in its movements compared to other hummingbirds. It perches quite upright. Although not overly aggressive, males will sometimes chase other hummingbirds from their preferred floral resources. Both sexes produce a variety of high-pitched squeaking and twittering notes. Males have a primary song consisting of a long series of 12-18 whistled notes that curve upwards then descend at the end. This territorial song is used in interactions with rivals or to court females.
The breeding behavior of this species remains poorly studied in the wild. Breeding appears to occur in the wet season between May and July in Central America. Courting males perform aerial displays, flying in repeated arcs and dives to impress females. The nest is a compact cup constructed with plant fibers and spider webs on a low horizontal branch or tree fern. Lichens and bark strips camouflage the outside of the nest. The female lays two tiny white eggs. She incubates the eggs alone for 15-19 days until hatching. Nestlings are fed regurgitated food by the female and fledge at approximately 20-26 days old. Newly independent young continue to beg from the mother for some time after fledging.
While still fairly widely distributed, the white-tipped sicklebill has a moderately small global population estimated at less than 50,000 individuals. Its population trend appears to be decreasing but the decline is not yet steep enough to trigger threatened status. Habitat loss from deforestation poses the major threat across its range. The sicklebill is also potentially threatened by climate change diminishing dense tropical vegetation. However, it occurs in some protected areas and has an extensive range, so the IUCN Red List currently classifies Eutoxeres aquila as a species of Least Concern. Ongoing monitoring of population sizes is recommended to detect any future increases in endangerment risk.
The white-tipped sicklebill is a handsome and unique hummingbird adapted to feeding on specialized tropical flowers. Its striking plumage and long downcurved bill make it unmistakable within its range. while not currently considered a threatened species, habitat loss in Neotropical forests may put pressure on its population in the future. Further study of the feeding ecology, reproductive biology and movements of the white-tipped sicklebill can provide greater understanding of this elusive species. Protecting areas of primary rainforest will give the best chance for this amazing hummingbird to continue flourishing.