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A uniquely-patterned, medium-sized hummingbird, the adult male White-necked Jacobin has a blue head and chest, a sharply contrasting white nape, a green back and blackish wings. The White-necked Jacobin can be found in a variety of habitats from humid forest canopies, to tall second growth forests, and even in coffee and cacao plantations. White-necked Jacobin can be found within its broad range feeding on nectar and small arthropods; occasionally, many will concentrate at flowering trees where they are aggressive and even territorial to one another. Although uncommon throughout most of its large range, the White-necked Jacobin's population is believed to be stable, and consequently has not been placed on any threatened species lists.
11–12 cm; male 7·4–9 g (1), female 6–9·2 g (2, 1). Bill and feet black. Adult male with head and chest blue, broad white crescent on nape ; rest of upperparts bright green including elongated uppertail-coverts; belly and most of tail white , narrowly edged and tipped black. Plumage of adult female notoriously variable, apparently individually; perhaps half to two-thirds show the “typical” female plumage with blue-green breast heavily scaled with whitish, belly dull white, upperparts entirely green and tail mostly green with dark blue tip, outer rectrix with white outer edge and tip; the remainder have plumage more or less male-like with a few only distinguishable from adult male by their longer bills and shorter wings and tails (though overlaps exist in all measurements). Adult female may show plumages resembling those of juvenile as well as adult male . Proportions of male-like females may also vary geographically; much more study required. In young male, plumage varies from essentially female-like, but with more white in the tail, to male-like with more black in the tail; both female and young male sometimes show buffy stripes on malars and centre of rump; young female similarly variable but usually with less white in tail, often more bronzy on throat and chest. Race flabellifera larger.
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.Numerous races described, but almost all now lumped into nominate. Only Tobago birds, distinguishable by larger size, are generally separated, although some birds from Santa Marta Mts (NE Colombia) apparently as large; name tobagensis is a frequently used synonym of flabellifera. Two subspecies recognized.
Florisuga mellivora mellivora Scientific name definitions
Florisuga mellivora flabellifera Scientific name definitions
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 forest canopy and borders, nesting in understorey; semi-open habitats of various types, e.g. lighter woodland, coffee and cacao plantations; tall second growth; and gallery forest. Usually high in trees, lower at edges and clearings. Occurs from sea-level up to c. 900 m; rarely, perhaps seasonally, up to 1500 m or more.
Not well understood. In many areas reported to be common during some seasons, rare to absent in others, but no clear patterns evident on present information; at a study site in the Colombian Amazon, F. mellivora was locally abundant during Jul–Oct, when Erythrina fusca trees were in flower, but was only seen occasionally throughout rest of year (3). Nominate casual or accidental on Aruba and the Grenadines (Carriacou), with the first record in Argentina in Feb 2016 (Buenos Aires province) (4).
Diet and Foraging
Visits flowers of a variety of trees, including Lisianthus axillaris (Gentianaceae), Pseudobombax septenatum (Bombaceae) (5), Inga, Erythrina, Bauhinia (Fabaceae), Vochysia (Vochysiaceae) and Symphonia (Clusiaceae), epiphytes (Norantea guianensis (6), Columnea, bromeliads), shrubs and <em>Heliconia</em> (Heliconiaceae) along edges and in clearings. Many concentrate at flowering trees, where they are aggressive but infrequently territorial; also at Heliconia. Both sexes hawk flies for long periods, hovering and darting high above streams and clearings, or sallying from treetop perches; less often gleans foliage, female sometimes in understorey. Arthropod food mainly small Diptera and Hymenoptera, some individuals recorded taking ants.
Sounds and Vocal Behavior
Rather silent. Song a long series of high-pitched single notes, repeated at rate of c. 0.7–1 note/second “tseee....tseee....tseee....tseee....”. Calls include a short “tsik”, sometimes doubled “tsi-sik”, also a longer, high-pitched “sweet”, and a descending “swee-swee-swee-swee” in antagonistic interactions.
Dry to early wet seasons: Jan–Jun or Jul in Costa Rica and Panama; Feb–May in NW Colombia, Jun and Nov in E Colombia; Mar in S Venezuela (7); Dec–Mar in Amazonian Brazil, with one record of female with egg in oviduct in Jul (1). Nest a rather shallow soft, felted cup of light-coloured plant down and cobweb, on flat upper surface of broad leaf of understorey palm (Geonoma, Asterogyne), where sheltered from above by another such leaf, 1–3 m above ground, sometimes near a stream; nest height 40 mm, external diameter 75 mm, internal diameter 27 mm (1). Female performs erratic, rising and falling, butterfly-like flight (of 0–3 m) (8) to distract potential predators from the whereabouts of its nest (9). During breeding season chases and displays by male-plumaged birds noted in canopy and along edges, but not known to form leks. No further information.
Not globally threatened (Least Concern). CITES II. Uncommon to common, at least seasonally, over most of its broad range and appears well able to use disturbed and man-made habitats such as tree plantations. Occurs regularly within many protected areas, including Corcovado National Park (Costa Rica), Los Katíos and Amacayacu National Parks (Colombia), Guatopo and Sierra Nevada National Parks (Venezuela), Asa Wright Nature Centre (Trinidad) and the mosiac of conservation units within the Serra dos Carajás National Park (Brazil).