A tiny hummingbird. In good light the Scintillant is unmistakable, though if glimpsed without a size reference, it could be mistaken for several other hummingbirds. The adult male has a large irridescent orange gorget that can appear yellow, redish, or black at different viewing angles. The gorget includes prominent ‘tails’ that project laterally from the lower corners, and the wings produce a distinctive trill during flight. The bill is relatively short, slightly shorter than the head. The back is green and grades into a light rufous on the sides and belly. The rufous tinge is important for identification: the female and immature birds, which lack the gorget or wing trill, can be identified by the combination of tiny size, a short bill, and rufous-tinged plumage (compare Volcano Hummingbird Selasphorus flammula: see pictures).
Other tiny hummingbirds co-occurring with the Scintillant are the Snowcap (Microchera albocoronata), Volcano Hummingbird (Selasphorus flammula), and Fork tailed Emerald (Chlorostilbon canivetii). The species most likely to be confused with the Scintillant is the Volcano Hummingbird. While male Scintillant’s gorget makes it unmistakable, female Scintillant have a rufous sides and belly whereas the female volcano is gray with no rufous.
The Glow-throated Hummingbird (Selasphorus ardens) also is similar to the Scintillant, but as far as is known, the two are allopatric. The male Glow-throated has a darker, more reddish gorget and less rufous in the body. The female Scintillant differs from Glow-throated in tail shape and coloration, and Scintillant has more rufous than does Glow-throated. The tail is also different in Scintillant and Glow-throated: male Scintillant R2 has greater emargination than does ardens, and most individual Scintillant have less dark in the central stripe running down R1 than does Glow-throated (see Figure 1 of Stiles 1983). The female tails are likewise subtly different: In ardens, the dark subterminal patch on R2 does not creep up the rachis to the same degree that it does in scintilla (see Figure 1 in Stiles 1983).
Ridgway (1911: 607-608) offers the following description of the Scintillant Hummingbird:
“Adult male.—Above metallic golden or bronzy green, the upper tail-coverts mostly cinnamon-rufous basally and laterally; rectrices cinnamon-rufous, the middle pair with a broad, fusiform mesial stripe of purplish black, extending for nearly the entire length, the next two (on each side) with a similar but broader and more cuneate stripe, the two outer pairs (on each side) with outer web and part of inner web purplish black; remiges purplish dusks, the inner secondaries glossed with bronze-green, the primary coverts similar in color to primaries but darker; loral and orbital regions deep cinnamon-rufous; chin and throat (gorget) brilliant metallic orange-red or orange (less scarlet than in S. rufus and S. [sasin]), changing to golden green in position d; chest dull white, tinged with cinnamon-buff posteriorly, the feathers dusky gray beneath surface; rest of under parts pale cinnamon-rufous or cinnamon-buff, paler medially, the sides (especially sides of breast) spotted with metallic bronze-green; bill dull black, the mandible paler basally; iris dark brown; feet grayish brown or dusky.”
“Adult female.—Above similar in color to adult male, but slightly duller (especially on pileum); middle rectrices metallic bronze-green margined with cinnamon or pale cinnamon-rufous, the remaining rectrices cinnamon-rofous for basal half, the terimal half crossed by a broad subterminal band of black and broadly tipped with pale cinnamon-rufous or cinnamon-buff; chin and throat varying from dull buffy white to pale cinnamon-rufous, more or less streaked or spotted with dusky grayish brown or dull bronzy; rest of under parts as in adult male, but sides without green spotting; bill, etc., as in adult male.”
“Young male.—Similar to the adult female, but middle rectrices mainly cinnamon-rufous.
Young female.—Similar to the adult female, but under parts strongly suffused with pale cinnamon-rufous, especially on throat, and feathers of upper parts indistinctly margined terminally with rusty.”
Young birds are likely to have corrugations on the bill, as do all relatives that have been studied (Yanega et al. 1997).
Molt occurs after breeding, late in the dry season, beginning in March/April and ending in July/August for adults (Stiles 1983). Adults have on average completely replaced one primary feather in April, and completely molted wings by August (figure 5 from Stiles 1983). Individual birds may be on varying molt schedules, and first-year birds undergoing first prebasic molt likely molt later than older individuals, sometimes as late as November (Stiles 1983). Specific pattern of molting not known to differ from general hummingbird pattern (e.g. Stiles 1995).
Legs dark. Iris dark brown, will appear black at most angles/distances. Bill black, "becoming fuscous on the base of the mandibular rami" (Wetmore 1968). No other bare parts.
See Table 1 for standard measurements. The liver is ~0.75% of the bird’s body mass (Hartman and Brownell 1959)
Table 1. Morphological measurements of Scintillant Hummingbird, in mm and g (mean ± s.d, range, n). % are of body mass.
|category||wing chord||tail length||exposed culmen||body mass||Pectoralis %||Supracoracoideus %||Heart %||Reference|
|Adult male||32.7 (31-34) (13)||23.5 (22-24.5) (13)||10.5 (10-11) (13)|| || || || ||Ridgway 1911|
|Adult female||35.7 (34-37.5) (10)||22.5 (21-23.5) (10)||11.9 (11.5-12.5) (10)|| || || || ||Ridgway 1911|
|Adult male|| || || ||2.05 ± 0.03a (12)||17.9 ± 0.56a (6)||9.36±0.41a|
|2.75 (6)||Hartman 1961|
|Adult female|| || || ||2.24 ± 0.06a|
|18.0 (2)||8.8 (2)||2.36|
|Adult male||32.7 ±0.7 (46)||23.6 ± 0.6 (46)||10.8 ± 0.4 (44)||2.12 ± 0.1 (8)|| || || ||Stiles 1983|
|Adult female||35.8 ± 0.7 (39)||22.8 ± 0.7 (39)||12.0 ± 0.6 (38)||2.33 ± 0.1 (7)|| || || ||Stiles 1983|
|Immature male||34.6 ± 1.1 (21)||27.7 ± 0.7 (21)||10.7 ± 0.6 (20)||2.15 ± 0.16 (5)|| || || ||Stiles 1983|
|Immature female||36.1 ± 0.9 (18)||22.6 ± 0.7 (17)||11.8 ± 0.4 (16)||2.30 ± 0.11 (4)|| || || ||Stiles 1983|
a ± se rather than sd.