Ruby-throated hummingbird (Archilochus colubris)

GenusArchilochus (1)
SizeLength: 9 cm (2)
Male weight: c. 3 g (2)
Female weight: c. 3.3 g (2)

The ruby-throated hummingbird is classified as Least Concern on the IUCN Red List (1) and is listed on Appendix II of CITES (3).

The most widespread of all hummingbird species, the ruby-throated hummingbird (Archilochus colubris) is a familiar inhabitant of Central and North America but is often only seen as a flash of green and red as it zips between flowers at remarkable speed. A brilliant, tiny, precision-flying bird, with narrow wings adapted for hovering, the ruby-throated hummingbird exhibits marked sexual dimorphism. The male is recognised by its iridescent, ruby red gorget, which covers the entire throat, and by its black face and chin and entirely dark, deeply-forked tail. The larger female and the immature bird lack the gorget, instead possessing a white chin and throat with variable amounts of thin, dark streaking, and have a dark, slightly-forked tail with white edging. All ruby-throated hummingbirds have a bright, metallic-green back and crown, which often appears darker on the males, and white underparts with greenish flanks. The plumage of the ruby-throated hummingbird, however, varies with the intensity of the light and, consequently, often appears almost black. The ruby-throated hummingbird has a long, straight, thin bill which allows it to extract nectar from deep flowers (2) (4) (5) (6) (7). Its feet are poorly developed and weak, a feature hinted at in the name of the order, Apodiformes, which means footless (8). Its vocalisations include a weak, mouse-like, twittering, squeaky call (9). 

Eastern America’s sole breeding hummingbird, the ruby-throated hummingbird is a migratory species that breeds in eastern North America, as far north as the southern limit of dense boreal forests, and winters in Central America, from south Sinaloa and south Veracruz, Mexico, to Belize, Honduras, Guatemala, El Salvador, Nicaragua and, sometimes, extreme western Panama. It is also a regular winter visitor to central and southern Florida and the Gulf coast of Louisiana and Texas (4) (5) (6) (10). Despite its miniscule size, the ruby-throated hummingbird is capable of remarkable non-stop migrations across the Gulf of Mexico, a round trip of more than 1,600 kilometres (4).

Primarily a woodland bird, the ruby-throated hummingbird is often found at the boundary between deciduous woodland and meadow, where it is most closely associated with mature trees, in which it nests, and a variety of flowering species, which provide it with nectar and small insects – both of which make up its diet. The ruby-throated hummingbird is well adapted to human presence and altered landscapes and, consequently, is also often found in suburban gardens, around hedgerows, pastures, wooded parks, orchards and fields. In parts of its breeding range it also occurs in pine stands. In its wintering range the ruby-throated hummingbird mainly occupies tropical dry forests and scrub habitats (2) (4) (5) (10).

The diminutive hummingbirds display remarkable manoeuvrability in flight, capable of hovering whilst feeding, as well as flying backwards, with up to 200 wing beats per second. Owing to this energy demanding behaviour, hummingbirds feed almost exclusively on nectar, the carbohydrate-rich sugar secretions of plants, and feed from as many as 1,000 to 2,000 flowers each day. Hummingbirds also have the highest oxygen requirement of any vertebrate and, as a result, have uniquely structured lungs that enable them to breathe at a rate of up to 500 breaths per minute. These physiological adaptations have allowed hummingbirds to occupy a vast array of habitats and altitudes throughout the Americas (11). 

Extremely active during the day (12), the ruby-throated hummingbird feeds on the nectar of orange and red flowers, with the male bird aggressively defending the flowers in its territory by spectacular chases and fights (6) (9). The ruby-throated hummingbird supplements this diet by catching insects in the air or by plucking them off spiders’ webs (6), and by taking advantage of ‘sapsucker wells’, a series of small holes in tree trunks drilled by woodpeckers from which sap oozes, attracting small insects (5). 

After wintering in the southern portion of its range, the male ruby-throated hummingbird returns to its breeding grounds in late March to establish and defend a breeding territory. The females return seven to ten days later, and the males seek to attract the attention of a potential mate with elaborate courtship flights by flying upwards to 15 metres or more, and then diving at top speed, pulling up at the last moment to complete a U-shaped pattern. The sound of the male’s wings are particularly loud in courtship flight, and may be accompanied by vocalisations (5). Courtship is very brief, and once mated, the male ruby-throated hummingbird abandons the female and may begin the southward migration as early as August (13). The female then selects a nest site, often atop a small, downward-slanting branch overhanging an open area or stream (5), and constructs the nest out of spider silk, lichens and vegetation. Two eggs are usually laid and incubated for 12 to 16 days (13), with the female at the nest for 50 to 55 minutes out of each hour (5). After leaving the nest, the young ruby-throated hummingbirds are fed by the female for around 10 days (13).

The ruby-throated hummingbird is a common, widespread species that is thought to be steadily increasing in number, estimated at around 27 percent per decade (14). It has likely benefited from the provision of bird feeders and flowers in urban areas, which increases the availability of food to the species, particularly in its breeding range (4). Some populations of the ruby-throated hummingbird in the eastern United States, however, are reported to be declining, although the reasons for this are currently unclear. Habitat destruction due to agricultural growth and deforestation may pose a threat to the species as it depends on specific forest plants for nesting and feeding (15), while it is known to be absent from some areas where the use of herbicides is prevalent (4). In addition, the ruby-throated hummingbird may be susceptible to predation by domestic cats and collisions with windows at bird feeders (6).

In the absence of any major threats to the species, the ruby-throated hummingbird has not been the target of any known conservation measures. Its breeding populations in the United States have been surveyed on several occasions and around 200,000 ruby-throated hummingbirds were banded in North America in the last century (4) (5), but there is still limited information available on the status of some of its populations, particularly in the wintering parts of its range. The ruby-throated hummingbird and its habitat receives a degree of protection in several conservation areas, including the Manuel Antonio National Park in Costa Rica (2).

For more information on the ruby-throated hummingbird and other bird species, see:

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  1. IUCN Red List (December, 2010)
  2. del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World. Volume 5: Barn-Owls to Hummingbirds. Lynx Edicions, Barcelona.
  3. CITES (December, 2010)
  4. Robinson, T.R., Sargent, R.R., and Sargent, M.B. (1996) Ruby-throated hummingbird (Archilochus colubris). In: Poole, A. (Ed.) The Birds of North America Online: Cornell Lab of Ornithology, Ithaca: Available at:
  5. Operation Ruby Throat (December, 2010)
  6. The Cornell Lab of Ornithology – All About Birds: Ruby-throated hummingbird (December, 2010)
  7. U.S. Geological Survey – Ruby-throated hummingbird (December, 2010)
  8. Erritzoe, J. (1993) The Birds of CITES and How to Identify Them. The Lutterworth Press, Cambridge.
  9. Vermont Fish and Wildlife Department (December, 2010)
  10. United States Department of Agriculture – Ruby-throated hummingbird (December, 2010)
  11. Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
  12. South Dakota Birds and Birding – Ruby-throated hummingbird (December, 2010)
  13. – Ruby-throated hummingbird (December, 2010)
  14. BirdLife International – Ruby-throated hummingbird (December, 2010)
  15. Rainforest Alliance – Ruby-throated hummingbird (December, 2010)