Adult male The upperparts, including the back, scapulars, upperwing coverts, rump, and uppertail coverts are metallic golden-green to emerald-green. The flight feathers (primaries, secondaries) are dark grey to blackish, with the tips of the primaries noticeably pointed. The tail is moderately forked (most apparent when spread) and is dark grey or blackish, with the central feathers metallic golden-green to bluish-green. The underparts are dingy-white to buffy-white with extensive metallic green mottling on the sides and a brownish wash on the undertail coverts (often with a few metallic green flecks). There is a pronounced white area across the upper chest and sides of the neck that forms a pseudo-collar just below the gorget. The crown and nape are metallic golden-green to emerald-green, like the upperparts. The ear coverts are dull blackish and there is a small white spot behind the eye. The chin is blackish but the remainder of the throat is bright iridescent red but appears blackish or golden unless viewed in direct sunlight. The iris is dark, the long, needle-like, straight bill is blackish, and the legs and feet are dusky.
Adult female The upperparts (back, scapulars, upperwing coverts, rump, uppertail coverts) are metallic golden-green to emerald-green with dark grey or blackish flight feathers. The tail is shallowly forked; the central tail feathers are metallic green (like the upperparts) but the remainder of the feathers are blackish with a green base and white tips; the white is most extensive on the outermost tail feathers and becomes less extensive towards the central feathers. The underparts are dingy-white with a dusky-buff wash on the sides (often relatively bright buff near the legs) and often a brighter white area across the upper chest forming a pseudo-collar. The crown and nape are metallic golden-green to emerald-green, like the upperparts, but the crown may become dusky and grayish in the fall when the plumage is worn. The ear coverts are dingy dusky-grey and the lores are darker grey, and there is a small white spot behind the eye. The chin and throat are whitish, often with faint lines of dusky flecks radiating from the chin; old individuals sometimes have one to several small, iridescent red spots on the throat. Bare part colouration is as in the adult male.
Juvenile / Immature This plumage is held throughout the summer of the first year, with adult plumage gradually acquired on the wintering grounds between September and March. It is similar to the plumage held by the adult female, but when fresh shows extensive fine buffy fringes on the upperparts and a stronger buffy wash on the sides and flanks. Immature males tend to show darker, more defined lines of dark flecks on the throat than either adult or immature females, and usually sport several incoming iridescent red throat feathers.
Adult males are distinctive within the context of the normally-occurring hummingbird species in B.C., but are quite similar to male Broad-tailed Hummingbird that has occurred as a vagrant in southern B.C. This identification concern is more applicable to birds observed in southern portions of the province, where either species could occur as a vagrant. Male Broad-tailed Hummingbird is distinguished from male Ruby-throated by its magenta-rose (rather than bright red) gorget that lacks the black chin, and the lack of a blackish “mask” through the eyes as is present in Ruby-throated. In Broad-tailed Hummingbird, the eyes are set in a pale dusky area above the gorget that extends under the chin. The tail is much more shallowly forked in Broad-tailed, appearing rather square-tipped when spread, with rufous edges on the inner feather and sometimes pale or whitish spots on the outer feathers. In addition, modified outer primaries of Broad-tailed produce a unique, buzzy wing-trill in flight that is not produced by Ruby-throated Hummingbird. Adult male Ruby-throated Hummingbird may also be confused with male Anna’s Hummingbird if seen briefly or if the iridescent crown of Anna’s Hummingbird is not apparent or appears dark (as occurs in certain lights). The gorget (and crown) of male Anna’s Hummingbird is iridescent rose-pink, rather than red as in Ruby-throated, and the underparts are heavily marked with dusky-grey and metallic green mottling (much less extensive in Ruby-throated). Anna’s Hummingbird is also a somewhat larger, bulkier bird with a relatively heavier bill. If the colour of the gorget is not apparent, male Ruby-throated could be confused with male Black-chinned Hummingbird. The Black-chinned, however, is a dingier and greyer bird on average (especially when worn), with a slightly longer and droopier bill and a tendency to wag and spread its tail habitually while feeding or hovering (rarely performed by Ruby-throated). The shape of the primaries, as visible on a perched bird, provides the most reliable mark for differentiating these two species. In Ruby-throated Hummingbird, the primaries are all relatively narrow, tapered, and pointed at the tips, whereas in Black-chinned Hummingbird they are relatively blunt and rounded.
The identification of female and immature Ruby-throated Hummingbird can be particularly difficult, especially with out-of-range birds, and should be approached cautiously. Female and immature Black-chinned Hummingbirds are extremely similar to Ruby-throated, and many individuals require exceptional views to determine their true identity. Black-chinned Hummingbird is a duller, greyer bird (especially on the crown) but this requires experience or direct comparison in order to be useful. The shape of the primaries, shape of the bill, and hovering behaviour, as mentioned above for the male, are similarly useful for identifying females and immatures and are the most important distinguishing features. Female Costa’s Hummingbird, which could occur as a vagrant in B.C., is very similar to female Ruby-throated but has a shorter tail (wingtips barely exceed tail on perched Costa’s, but shorter than tail on perched Ruby-throated) and, like female Black-chinned, tends to be a slightly duller, greyer bird with less contrasting and bright green colouration on the crown and upperparts. Also similar to female Ruby-throated, the female Anna’s Hummingbird is a somewhat larger, bulkier, bigger-headed bird with darker and more extensive dusky-grey mottling over the underparts and more pronounced green mottling on the sides and flanks. As well, female Anna’s Hummingbirds typically show several iridescent rose-red spots on the throat (these are infrequent in female Ruby-throated, but are shown by immature males). Other potential confusion species in B.C., such as Rufous Hummingbird and Calliope Hummingbird have a brighter and more extensive buffy or rufous-buff wash on the sides and flanks. Additionally, female Calliope has a very short tail (not exceeding the primaries when perched) and is a noticeably smaller bird.
Male produces a monotonous series of chip notes at dawn that functions as a song, as well as a scratchy, jumbled series of notes from a high perch following copulation. Other calls include a soft, somewhat nasal or twangy tchew or tchup, as well as a quiet tic-tic by the female during feeding. During territorial encounters, gives a series of harsh, rapid, squeaky twitters, chirps, and squeals. Both sexes give a repetitive chee-dit during fall migration. This is the only North American hummingbird whose nestlings are known to produce begging calls.
Source: Robinson et al. (1996); Williamson (2001); Howell (2002)
Courtship Like most temperate hummingbirds, this species has an elaborate courtship display that begins immediately after arriving on the breeding grounds. Two types of courtship displays are given, known as the “Dive Display” and the “Shuttle Display.” During the “Dive Display,” which begins once a female has entered the male’s territory, the male undertakes a series of U-shaped looping dives that can begin as high as 15 m above the female and bottom-out at 3-10 m above the female. This display is also used to deter invaders into the territory, so it is not strictly a courtship display. Once the female has perched, the male then begins the “Shuttle Display” which involves a series of very rapid side-to-side horizontal arcs with the gorget flared. This display is done within 0.5 m of the perched female, and is usually accompanied by a loud and exaggerated wing buzz. Following mating, the male largely abandons the female.
Nest Nest-building begins shortly after arrival on the breeding grounds (late May or early June in B.C.), immediately following courtship and mating. The construction process generally takes 5-10 days and is done entirely by the female. The nest is a small cup (4.5-5 cm across, with an inner diameter of 2.5-3 cm) and is situated near the tip or at a fork of a down-sloping or horizontal branch with a fairly open area underneath and a canopy of leaves above. The nest is often situated near, or even above, water. Nest heights range from 3-6 m, although they can sometimes be found as low as 1.5 m or as high as 15 m. The nest is composed primarily of plant down (thistle, dandelion) and bud scales and is held together with spider webs; it sometimes contains animal hairs and other fibres. The exterior is decorated with lichens for camouflage.
Eggs Clutches of (1) 2 (3) smooth, non-glossy, white eggs are laid following the completion of the nest, and most eggs in B.C. are likely laid in early or mid-June. The incubation period is 12-16 days, and only the female incubates the eggs. This species produces 2-3 clutches per year in some areas, but B.C. populations (which are at the northernmost portion of the species’ range) likely produce only one or two clutches per year. Most eggs in B.C. likely hatch in mid- to late June, although some may potentially be delayed and hatch in early July (particularly replacement clutches).
Young Following hatching, the young remain in the nest for 18-22 days and are tended only by the female; they are also tended by the female for an additional 5-7 days after fledging. The nestlings are altricial and nearly naked, with slate-blue skin and a line of yellowish down along the centre of the back; the bill is short and yellow. Nestlings in B.C. are likely present between mid-June and mid-July, and some fledglings may remain into late July or early August before migrating south.
Source: Robinson et al. (1996); Baicich and Harrison (1997); Williamson (2001); Howell (2002)
As with most hummingbirds, nectar forms a large proportion of the diet of this species. Reported nectar sources that occur naturally in the Peace River region include Wild Bergamot, columbine, honeysuckle, paintbrush, and campion, and it would also be expected to draw nectar from a wide variety of exotic and ornamental flowers and flowering shrubs. It sometimes pierces the base of long-tubed flowers to gain access to the nectar. It also consumes small insects such as mosquitos, spiders, gnats, small caterpillars, aphids, fruit flies, and small bees, and has been known to consume insect eggs from vegetation. Most insects are captured either by “hawking” from a perch or through gleaning of the vegetation, and it is known to glean insects that are attracted to sap wells. It also sometimes consumes the sap that seeps from these wells. Regularly visits feeders. When feeding, the Ruby-throated Hummingbird typically holds its tail closed or slightly fanned and in the same plane as the rest of the body. The tail is occasionally twitched or dipped, but is not habitually wagged as in the similar Black-chinned Hummingbird.
Source: Robinson et al. (1996); Williamson (2001); Howell (2002)
Most records in B.C. (both breeding season records and vagrants) are from feeders in residential areas, with nearby habitats consisting of deciduous or mixed forests, gardens, forest edges, and shrubs. A single July vagrant record from the Lower Mainland is from a brushy montane area away from human habitation, but most vagrants would be expected at feeders.
Breeds across Canada from northern Alberta (and possibly northeastern B.C.) east to southern Quebec and Nova Scotia. It breeds widely throughout the eastern United States from the eastern Great Plains east to the Atlantic coast and south to southern Texas and the Gulf coast (except southernmost Florida). It winters from southern and western Mexico south through most of Central America to Costa Rica, with a few individuals remaining in southern Florida and occasional birds elsewhere along the Atlantic and Gulf coasts of the U.S. It is a casual vagrant in the western U.S. and Canada during migration, but may often be overlooked among the abundant and very similar Black-chinned Hummingbird.
Breeding The Ruby-throated Hummingbird is rare but regular during the breeding season in the Peace River area of northeastern B.C. It is most commonly encountered near Taylor, which is 40 km west of the Alberta border, but additional breeding season records exist south to Dawson Creek and Tupper. There has been no definitive confirmation of breeding in the province, but the annual occurrence of multiple individuals of both sexes near Taylor (for at least 30 years based on anecdotal accounts by local residents), paired individuals near Dawson Creek, and apparent immature/juvenile individuals along the Peace River all suggest that a tiny breeding population exists in the region as an extension of larger populations in nearby Alberta.
Migration and Vagrancy The earliest records on file from the Peace River area are from late May (May 20), although most records span the period from early June through July. Consequently, it appears that breeders arrive in late May or early June and depart by late July or early August. A single apparent fall migrant from the Peace River area (August 16, near Dawson Creek) suggests that fall migration in this region may extend at least as late as mid-August.
Elsewhere in B.C., this species is a casual spring (April-May) and fall (mid-July to late August) vagrant to the south coast, including the Lower Mainland and Vancouver Island. It is also accidental during fall migration (mid-August) in the central interior (New Hazelton) and accidental in spring (May) in extreme northeastern B.C. north of the Peace River lowlands (Sikanni Chief River). An additional summer record for the central interior (Vanderhoof, June 1951) is not fully documented but may be legitimate. Until recently, records of vagrants outside of the Peace River area had not been confirmed by definitive photographic evidence and were therefore often open to speculation; however, records from New Hazelton in 2007 and Vancouver Island in 2008 have both been well-photographed and have established this species as an unquestionable vagrant west of the Rocky Mountains.
Source: Campbell et al. (1990b)
Population and Conservation Status
At a continental level, populations of this species are generally stable or even increasing in some areas (Robinson et al. 1996). The Ruby-throated Hummingbird was considered an accidental vagrant to the Peace River region by Campbell et al. (1990b), but it is now known to be a rare but regular component of that region’s avifauna and a likely (though unconfirmed) breeder. The increase in records over the past two decades may reflect an actual population increase in B.C. or, more likely, greater awareness of its presence in the region and therefore greater emphasis placed on documenting its occurrence. It may simply have been overlooked by previous authors, as indicated by anecdotal reports of its presence in northeastern B.C. for at least the past 30 years by local residents. This portion of the province had received relatively scant and irregular coverage by birders and ornithologists prior to the 1990s and much has been learned of the distribution and status of birds in the region since that time.
Within B.C., this species is still classified as “Accidental” by the B.C. Conservation Data Centre, and therefore does not receive a conservation designation in the province. Recent revelations about its abundance in northeastern B.C., however, may result in a future designation as a “species at risk” in the province. Based on the criteria used to determine these designations, the Ruby-throated Hummingbird would likely receive the highest level of conservation priority and be placed on the “red-list” as an endangered species in B.C.
The Ruby-throated Hummingbird is monotypic, with no recognized subspecies. It is closely related to the Black-chinned Hummingbird, with which it forms a superspecies, and together they comprise the genus Archilochus. These two species may hybridize on occasion in Texas, but this has not been definitively shown; the range of this species overlaps very little with other hummingbird species which limits the potential for hybridization. The genus Archilochus is very closely related to several other genera of temperate hummingbirds such as Selasphorus, Stellula, and Calypte.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2023-09-24 1:41:44 PM]
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