Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With approximately 375 species and 113 genera,<!--Do not archive the IUCN ref, as it changes with updates--> they occur from Alaska to Tierra del Fuego, but most species are found in Central and South America. As of 2026, 21 hummingbird species are listed as endangered or critically endangered, with about 255 species declining in population.
Hummingbirds have varied specialized characteristics to enable rapid, maneuverable flight: exceptional metabolic capacity, adaptations to high altitude, sensitive visual and communication abilities, and long-distance migration in some species. Among all birds, male hummingbirds have the widest diversity of plumage color, particularly in blues, greens, and purples. Hummingbirds are the smallest mature birds, measuring in length. The smallest is the bee hummingbird, which weighs less than , and the largest is the giant hummingbird, weighing . Noted for long beaks, hummingbirds are specialized for feeding on flower nectar, but all species also consume small insects.
Hummingbirds are known by that name because of the humming sound created by their beating wings, which flap at high frequencies audible to other birds and humans. They hover at rapid wing-flapping rates, which vary from around 12 beats per second in the largest species to 99 per second in small hummingbirds.
Hummingbirds have the highest mass-specific metabolic rate of any homeothermic animal. To conserve energy when food is scarce and at night when not foraging, they can enter torpor, a state similar to hibernation, and slow their metabolic rate to of its normal rate. While most hummingbirds do not migrate, the rufous hummingbird has one of the longest migrations among birds, traveling twice per year between Alaska and Mexico, a distance of about .
Hummingbirds split from their sister group, the swifts and treeswifts, around 42 million years ago. The iridescent colors and highly specialized feathers of many species (mainly in males) give some hummingbirds exotic common names, such as sun gem, fairy, woodstar, sapphire or sylph. They have characteristic long, narrow beaks (bills) which may be straight (of varying lengths) or highly curved. The giant hummingbird is the largest, having a mass of – approximately twice as heavy as the next largest hummingbird – with a wingspan of and body length of .
Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling helicopter-like flight in any direction, including the ability to hover. Such extreme flight demands are supported by a high metabolic rate dependent on foraging for sugars from flower nectar. The toes of hummingbirds are formed as claws with ridged inner surfaces to aid gripping onto flower stems or petals. During flight, hummingbird feet are tucked up under the body, enabling optimal aerodynamics and maneuverability.
The sexes differ in feather coloration, with males having distinct brilliance and ornamentation of head, neck, wing, and breast feathers.
Hummingbird females build a nest resembling a small cup about in diameter, commonly attached to a tree branch using spider webs, lichens, moss, and loose strings of plant fibers (image).
As the nestlings develop juvenile plumage, they do more and more wing flapping as they develop their ability to fly. The nestlings finally leave the nest (fledge), but are initially awkward fliers still fed by their mother.
Nectar-feeding hummingbirds ingest large volumes of liquid which must be eliminated. Nestlings elevate their cloaca ejecting a stream of dilute liquid containing suspended fecal material beyond the rim of the nest.
The average lifespan of a ruby-throated hummingbird is estimated to be 3–5 years, with most deaths occurring in yearlings, Bee hummingbirds live 7–10 years. The ruby-throated hummingbird population the most populous North American hummingbird decreased by 17% over the early 21st century.
The hummingbird moth has flying and feeding characteristics similar to those of a hummingbird. Hummingbirds may be mistaken for hummingbird hawk-moths, which are large, flying insects with hovering capabilities, and exist only in Eurasia.
Range
Hummingbirds are restricted to the Americas from south central Alaska to Tierra del Fuego, including the Caribbean.
The greatest species richness is in humid tropical and subtropical forests of the northern Andes and adjacent foothills, but the number of species found in the Atlantic Forest, Central America or southern Mexico also far exceeds the number found in southern South America, the Caribbean islands, the United States, and Canada. Colombia alone has more than 160 and the comparably small Ecuador has about 130 species.
Taxonomy and systematics
The family Trochilidae was introduced in 1825 by Irish zoologist Nicholas Aylward Vigors with Trochilus as the type genus. In traditional taxonomy, hummingbirds are placed in the order Apodiformes, which also contains the swifts, but some taxonomists have separated them into their own order, the Trochiliformes.
Hummingbird wing bones are hollow and fragile, making fossilization difficult and leaving their evolutionary history poorly documented. Though scientists theorize that hummingbirds originated in South America, where species diversity is greatest, possible ancestors of extant hummingbirds may have lived in parts of Europe and what is southern Russia today.
As of 2025, 375 hummingbird species have been identified.
Fossils of birds not clearly assignable to either hummingbirds or a related extinct family, the Jungornithidae, have been found at the Messel pit and in the Caucasus, dating from 35 to 40 million years ago; this indicates that the split between these two lineages indeed occurred around that time. The areas where these early fossils have been found had a climate quite similar to that of the northern Caribbean or southernmost China during that time. The biggest remaining mystery at present is what happened to hummingbirds in the roughly 25 million years between the primitive Eurotrochilus and the modern fossils. The astounding morphological adaptations, the decrease in size, and the dispersal to the Americas and extinction in Eurasia all occurred during this timespan. DNA–DNA hybridization results suggest that the main radiation of South American hummingbirds took place at least partly in the Miocene, some 12 to 13 million years ago, during the uplifting of the northern Andes.
In 2013, a 50-million-year-old bird fossil unearthed in Wyoming was found to be a predecessor to hummingbirds and swifts before the groups diverged.
Evolution
Hummingbirds split from other members of Apodiformes, the insectivorous swifts (family Apodidae) and treeswifts (family Hemiprocnidae), about 42 million years ago, probably in Eurasia.
Phylogeny
A phylogenetic tree unequivocally indicates that modern hummingbirds originated in South America, with the last common ancestor of all living hummingbirds living around 22 million years ago. Molecular phylogenetic studies of the hummingbirds have shown that the family is composed of nine major clades. – the topazes, hermits, mangoes, brilliants, coquettes, the giant hummingbird, mountaingems, bees, and emeralds – defining their relationship to nectar-bearing flowering plants which attract hummingbirds into new geographic areas. When Edward Dickinson and James Van Remsen Jr. updated the Howard and Moore Complete Checklist of the Birds of the World for the 4th edition in 2013, they divided the hummingbirds into six subfamilies.
Molecular phylogenetic studies determined the relationships between the major groups of hummingbirds. The scientific names are those introduced in 2013.
While all hummingbirds depend on flower nectar to fuel their high metabolisms and hovering flight, coordinated changes in flower and bill shape stimulated the formation of new species of hummingbirds and plants. Due to this exceptional evolutionary pattern, as many as 140 hummingbird species can coexist in a specific region, such as the Andes range.
Upon maturity, males of a particular species, Phaethornis longirostris, the long-billed hermit, appear to be evolving a dagger-like weapon on the beak tip as a secondary sexual trait to defend mating areas.
Geographic diversification
The Andes Mountains appear to be a particularly rich environment for hummingbird evolution because diversification occurred simultaneously with mountain uplift over the past 10 million years. The same is true for the sword-billed hummingbird (Ensifera ensifera), one of the morphologically most extreme species, and one of its main food plant clades (Passiflora section Tacsonia).
Coevolution with ornithophilous flowers
thumb|[[Purple-throated carib feeding at a flower]]
The 375 hummingbird species are specialized nectarivores coevolved with some 7,000 plant species and ornithophilous flowers. The first plant clade to coevolve with hummingbirds in the Americas is likely Heliconia, estimated to have occurred over 16 to 23 million years ago. Some species, especially those with unusual bill shapes, such as the sword-billed hummingbird and the sicklebills, are coevolved with a small number of flower species. The bee hummingbird (Mellisuga helenae) – the world's smallest bird – evolved to dwarfism likely because it had to compete with long-billed hummingbirds having an advantage for nectar foraging from specialized flowers, consequently leading the bee hummingbird to more successfully compete for flower foraging against insects.
thumb|[[Lesser violetear at a flower]]
Coevolution "syndrome"
Hummingbirds and the plants they visit for nectar have a tight coevolutionary association, generally called a plant–bird syndrome or mutualistic network. By collecting pollen on their beaks while foraging from flowers, hummingbirds contribute to flower species diversification and morphology adaptations – hummingbirds prefer bright red, yellow or purple flowers having no scent or landing platform, and with long corolla tubes containing copious nectar, characteristics unfavorable to insect pollinators. Hummingbird-pollinated flowers also produce relatively weak nectar (averaging 25% sugars) containing a high proportion of sucrose, whereas insect-pollinated flowers typically produce more concentrated nectars dominated by fructose and glucose.
Hummingbirds show high specialization and modularity, especially in communities with high species richness.
Sexual dimorphisms
Hummingbirds exhibit sexual size dimorphism according to Rensch's rule, The extent of this sexual size difference varies among clades of hummingbirds. For example, the Mellisugini clade (bees) exhibits a large size dimorphism, with females being larger than males. For males and females of the same size, females tend to have larger bills. Thus, sexual selection favors smaller male hummingbirds. When sunlight hits these cells, it is split into wavelengths that reflect to the observer in varying degrees of intensity, and may also be colored by carotenoid pigmentation and more subdued black, brown or gray colors dependent on melanin.
One study of Anna's hummingbirds found that dietary protein was an influential factor in feather color, as birds receiving more protein grew significantly more colorful crown feathers than those fed a low-protein diet. Additionally, birds on a high-protein diet grew yellower (higher hue) green tail feathers than birds on a low-protein diet. Humming serves communication purposes by alerting other birds of the arrival of a fellow forager or potential mate. The humming sound of hummingbirds is unique among flying animals, compared to the whine of mosquitoes, buzz of bees, and "whoosh" of larger birds.
Visual system
thumb|left|Male rufous hummingbird (Selasphorus rufus) displaying a proportionally large eye in relation to its head
Hummingbirds have visual properties typical of species that are both predatory and prey, a combination that enables them to capture insects and to hover at flowers for feeding, while simultaneously avoiding potential predators.
Anatomy
Hummingbirds have an upper and lower eyelid, and a nictitating membrane as a translucent "third" eyelid.
The iris of hummingbird eyes is dark brown, with a black pupil measuring 216 micrometres in diameter, and a wide, thin cornea.
The prevalence of natural eye disease in a sample of Anna's and black-chinned hummingbirds was 2.3%. The enlargement of the brain region responsible for visual processing indicates an enhanced ability for perception and processing of fast-moving visual stimuli encountered during rapid forward flight, insect foraging, competitive interactions, and high-speed courtship.
Hummingbirds are highly sensitive to stimuli in their visual fields, responding to even minimal motion in any direction by reorienting themselves in midflight. While in complex and dynamic natural environments, their visual sensitivity allows them to precisely hover in place The fourth color cone would extend the range of visible colors for hummingbirds to perceive ultraviolet light and color combinations of feathers and gorgets, colorful plants, and other objects in their environment, enabling detection of as many as five non-spectral colors, including purple, ultraviolet-red, ultraviolet-green, ultraviolet-yellow, and ultraviolet-purple.]]
Many hummingbird species exhibit a diverse vocal repertoire of chirps, squeaks, whistles and buzzes. Vocalizations vary in complexity and spectral content during social interactions, foraging, territorial defense, courtship, and mother-nestling communication. It also produces ultrasonic vocalizations which do not function in communication.
thumb|Song of male Anna's hummingbird (Calypte anna)
The avian vocal organ, the syrinx, plays an important role in understanding hummingbird song production. What makes the hummingbird's syrinx different from that of other birds in the Apodiformes order is the presence of internal muscle structure, accessory cartilages, and a large tympanum that serves as an attachment point for external muscles, all of which are adaptations thought to be responsible for the hummingbird's increased ability in pitch control and large frequency range.
Hummingbird songs originate from at least seven specialized nuclei in the forebrain. A genetic expression study showed that these nuclei enable vocal learning (ability to acquire vocalizations through imitation), a rare trait known to occur in only two other groups of birds (parrots and songbirds) and a few groups of mammals (including humans, whales and dolphins, and bats).
Generally, birds have been assessed to vocalize and hear in the range of 2–5 kHz, with hearing sensitivity falling with higher frequencies. During flight and hovering, oxygen consumption per gram of muscle tissue in a hummingbird is about 10 times higher than that measured in elite human athletes.
Hummingbirds are rare among vertebrates in their ability to rapidly make use of ingested sugars to fuel energetically expensive hovering flight, powering up to 100% of their metabolic needs with the sugars they drink. Hummingbird flight muscles have extremely high capacities for oxidizing carbohydrates and fatty acids via hexokinase, carnitine palmitoyltransferase, and citrate synthase enzymes at rates that are the highest known for vertebrate skeletal muscle. To sustain rapid wingbeats during flight and hovering, hummingbirds expend the human equivalent of 150,000 calories per day, an amount estimated to be 10 times the energy consumption by a marathon runner in competition.
Hummingbirds can use newly ingested sugars to fuel hovering flight within 30–45 minutes of consumption. These data suggest that hummingbirds are able to oxidize sugar in flight muscles at rates rapid enough to satisfy their extreme metabolic demands as indicated by a 2017 review showing that hummingbirds have in their flight muscles a mechanism for "direct oxidation" of sugars into maximal ATP yield to support a high metabolic rate for hovering, foraging at altitude, and migrating. This adaptation occurred through the evolutionary loss of a key gene, fructose-bisphosphatase 2 (FBP2), coinciding with the onset of hovering by hummingbirds estimated by fossil evidence to be some 35 million years ago. Without FBP2, glycolysis and mitochondrial respiration in flight muscles are enhanced, enabling hummingbirds to metabolize sugar more efficiently for energy. The amount of fat (1–2 g) used by a migrating hummingbird to cross the Gulf of Mexico in a single flight is similar to that used by a human climbing about .
Heat dissipation
The high metabolic rate of hummingbirds – especially during rapid forward flight and hovering – produces increased body heat that requires specialized mechanisms of thermoregulation for heat dissipation, which becomes an even greater challenge in hot, humid climates. Hummingbirds dissipate heat partially by evaporation through exhaled air, and from body structures with thin or no feather covering, such as around the eyes, shoulders, under the wings (patagia), and feet.
While hovering, hummingbirds do not benefit from the heat loss by air convection during forward flight, except for air movement generated by their rapid wing-beat, possibly aiding convective heat loss from the extended feet. Smaller hummingbird species, such as the calliope, appear to adapt their relatively higher surface-to-volume ratio to improve convective cooling from air movement by the wings. requires a parallel dynamic range in kidney function. During a day of nectar consumption with a corresponding high water intake that may total five times the body weight per day, hummingbird kidneys process water via glomerular filtration rates (GFR) in amounts proportional to water consumption, thereby avoiding overhydration. During brief periods of water deprivation, however, such as in nighttime torpor, GFR drops to zero, preserving body water. Morphological studies on Anna's hummingbird kidneys showed adaptations of high capillary density in close proximity to nephrons, allowing for precise regulation of water and electrolytes.
Hemoglobin adaptation to altitude
Dozens of hummingbird species live year-round in tropical mountain habitats at high altitudes, such as in the Andes over ranges of to where the partial pressure of oxygen in the air is reduced, a condition of hypoxic challenge for the high metabolic demands of hummingbirds. In Andean hummingbirds living at high elevations, researchers found that the oxygen-carrying protein in blood hemoglobin had increased oxygen-binding affinity, and that this adaptive effect likely resulted from evolutionary mutations within the hemoglobin molecule via specific amino acid changes due to natural selection.
Adaptation to winter
Anna's hummingbirds are the northernmost year-round residents of any hummingbird. Anna's hummingbirds were recorded in Alaska as early as 1971, and resident in the Pacific Northwest since the 1960s, particularly increasing as a year-round population during the early 21st century. Scientists estimate that some Anna's hummingbirds overwinter and presumably breed at northern latitudes where food and shelter are available throughout winter, tolerating moderately cold winter temperatures. In addition, hummingbirds with inadequate stores of body fat or insufficient plumage are able to survive periods of subfreezing weather by lowering their metabolic rate and entering a state of torpor.
While their range was originally limited to the chaparral of California and Baja California, it expanded northward to Oregon, Washington, and British Columbia, and east to Arizona over the 1960s to 1970s. In the Pacific Northwest, the fastest growing populations occur in regions with breeding-season cold temperatures similar to those of its native range. and is a non-migrating resident of Seattle where it lives year-round through winter enduring extended periods of subfreezing temperatures, snow, and high winds.
Torpor
The metabolism of hummingbirds can slow at night or at any time when food is not readily available; the birds enter a deep-sleep state (known as torpor) to prevent energy reserves from falling to a critical level. with heart and breathing rates slowing dramatically (heart rate of roughly 50 to 180 bpm from its daytime rate of higher than 1000 bpm). Recordings from a Metallura phoebe hummingbird in noctural torpor at around in the Andes mountains showed that body temperature fell to 3.3 °C (38 °F), the lowest known level for a bird or non-hibernating mammal. During cold nights at altitude, hummingbirds were in torpor for 2–13 hours depending on species, with cooling occurring at the rate of 0.6 °C per minute and rewarming at 1–1.5 °C per minute.
Use and duration of torpor vary among hummingbird species and are affected by whether a dominant bird defends territory, with nonterritorial subordinate birds having longer periods of torpor. A hummingbird with a higher fat percentage will be less likely to enter a state of torpor compared to one with less fat, as a bird can use the energy from its fat stores. Among the better-known North American species, the typical lifespan is probably 3 to 5 years. The longest recorded lifespan in the wild relates to a female broad-tailed hummingbird that was banded as an adult at least one year old, then recaptured 11 years later, making her at least 12 years old. Other longevity records for banded hummingbirds include an estimated minimum age of 10 years 1 month for a female black-chinned hummingbird similar in size to the broad-tailed hummingbird, and at least 11 years 2 months for a much larger buff-bellied hummingbird.
Natural enemies
Predators
Where present, domestic cats are probably the most common predators of non-nested hummingbirds.
Praying mantises have been observed as predators of hummingbirds. Other predators include dragonflies, frogs, orb-weaver spiders, small predatory birds such as Sharp-shinned Hawks and American Kestrels, snakes, and other birds such as the roadrunner.
Parasites
Hummingbirds host a highly specialized lice fauna. Two genera of Ricinid lice, Trochiloecetes and Trochiliphagus, are specialized on them, infesting about 14% in one study of 22 species. In contrast, two genera of Menoponid lice, Myrsidea and Leremenopon, are rare on them.
Reproduction
thumb|Video of a hummingbird building a nest
Male hummingbirds do not take part in nesting. Most species build a cup-shaped nest on the branch of a tree or shrub. The nest varies in size relative to the particular species – from smaller than half a walnut shell to several centimeters in diameter. The unique properties of the silk allow the nest to expand as the young hummingbirds grow. Two white eggs are laid,
Flight
thumb|left|A female ruby-throated hummingbird hovering in mid-air
Hummingbird flight has been studied intensively from an aerodynamic perspective using wind tunnels and high-speed video cameras. Two studies of rufous or Anna's hummingbirds in a wind tunnel used particle image velocimetry techniques to investigate the lift generated on the bird's upstroke and downstroke. The birds produced 75% of their weight support during the downstroke and 25% during the upstroke, with the wings making a "figure 8" motion.
thumb|upright=0.7|Hummingbirds generate a trail of wake [[Vortex|vortices under each wing while hovering.]]
Many earlier studies had assumed that lift was generated equally during the two phases of the wingbeat cycle, as is the case of insects of a similar size. Presumably due to rapid wingbeats for flight and hovering, hummingbird wings have adapted to perform without an alula.
The giant hummingbird's wings beat as few as 12 times per second, and the wings of typical hummingbirds beat up to 80 times per second. As air density decreases, for example, at higher altitudes, the amount of power a hummingbird must use to hover increases. Hummingbird species adapted for life at higher altitudes, therefore, have larger wings to help offset these negative effects of low air density on lift generation.
A slow-motion video has shown how the hummingbirds deal with rain when they are flying. To remove the water from their heads, they shake their heads and bodies, similar to a dog shaking, to shed water. Further, when raindrops collectively may weigh as much as 38% of the bird's body weight, hummingbirds shift their bodies and tails horizontally, beat their wings faster, and reduce their wings' angle of motion when flying in heavy rain.
Wingbeats and flight stability
thumb|Slow-motion video of hummingbirds feeding
The highest recorded wingbeat rate for hummingbirds during hovering is 99.1 per second, as measured for male woodstars (Chaetocercus sp.).
During turbulent airflow conditions created experimentally in a wind tunnel, hummingbirds exhibit stable head positions and orientation when they hover at a feeder. When wind gusts from the side, hummingbirds compensate by increasing wing-stroke amplitude and stroke plane angle and by varying these parameters asymmetrically between the wings and from one stroke to the next. This downward acceleration during a dive is the highest reported for any vertebrate undergoing a voluntary aerial maneuver; in addition to acceleration, the speed relative to body length is the highest known for any vertebrate. For instance, it is about twice the diving speed of peregrine falcons in pursuit of prey.
The outer tail feathers of male Anna's (Calypte anna) and Selasphorus hummingbirds (e.g., Allen's, calliope) vibrate during courtship display dives and produce an audible chirp caused by aeroelastic flutter. Hummingbirds cannot make the courtship dive sound when missing their outer tail feathers, and those same feathers could produce the dive sound in a wind tunnel. The sound is caused by the aerodynamics of rapid air flow past tail feathers, causing them to flutter in a vibration, which produces the high-pitched sound of a courtship dive.
Many other species of hummingbirds also produce sounds with their wings or tails while flying, hovering, or diving, including the wings of the calliope hummingbird, broad-tailed hummingbird, rufous hummingbird, Allen's hummingbird, and the streamertail species, as well as the tail of the Costa's hummingbird and the black-chinned hummingbird, and a number of related species. The harmonics of sounds during courtship dives vary across species of hummingbirds. The trill arises from air rushing through slots created by the tapered tips of the ninth and tenth primary wing feathers, creating a sound loud enough to be detected by female or competitive male hummingbirds and researchers up to 100 m away. Most hummingbirds live in the Amazonia-Central America tropical rainforest belt, where seasonal temperature changes and food sources are relatively constant, obviating the need to migrate. As the smallest living birds, hummingbirds are relatively limited at conserving heat energy, and are generally unable to maintain a presence in higher latitudes during winter months, unless the specific location has a large food supply throughout the year, particularly access to flower nectar. Other migration factors are seasonal fluctuation of food, climate, competition for resources, predators, and inherent signals. A few species are year-round residents of Florida, California, and the southwestern desert regions of the US. the rufous hummingbird migrates more extensively and nests farther north than any other hummingbird species, and must tolerate occasional temperatures below freezing in its breeding territory. This cold hardiness enables it to survive temperatures below freezing, provided that adequate shelter and food are available. and may be time-coordinated with flower and tree-leaf emergence in early spring, and also with availability of insects as food.
Feeding
thumb|Hummingbirds feeding; video recorded at 1,500 frames per second
thumb|Hummingbird visiting flowers in [[Copiapó, Chile: The apparent slow movement of hummingbird wings is a result of the stroboscopic effect.]]
thumb|thumbtime=30|[[Calypte anna|Anna's hummingbird on Salvia]]
All hummingbirds are overwhelmingly nectarivorous, Less accessible ornithophiles (for example, those requiring long bills) still rely on multiple hummingbird species for pollination. More importantly, hummingbirds tend not to be especially selective nectar-feeders, even regularly visiting non-ornithophilous plants, as well as ornithophiles which appear poorly suited for feeding by their species. Feeding efficiency is optimized, however, when birds feed on flowers better suited to their bill morphologies.
thumb|Heliconia species are popular nectar sources for many hummingbirds; here, a [[green-crowned brilliant (Heliodoxa jacula) visits Heliconia stricta]]
Although a high-quality source of energy, nectar is deficient in many macro- and micronutrients; it tends to be low in lipids, and although it may contain trace quantities of amino acids, some essential acids are severely or entirely lacking. Though hummingbird protein requirements appear to be quite small, at 1.5% of the diet, nectar is still an inadequate source; Insectivory is not thought to be calorically important; nonetheless, regular consumption of arthropods is considered crucial for birds to thrive. In fact, it has been suggested that the majority of non-caloric nutritional needs of hummingbirds are met by insectivory, but nectars do contain appreciable quantities of certain vitamins and minerals. (Here, "insectivory" refers to the consumption of any arthropod, not exclusively insects).
Though not as insectivorous as once believed, and far less so than most of their relatives and ancestors among the Strisores (e.g., swifts), insectivory is probably of regular importance to most hummingbirds. About 95% of individuals from 140 species in one study showed evidence of arthropod consumption, Some species have even been recorded to be largely or entirely insectivorous for periods of time, particularly when nectar sources are scarce, and possibly, for some species, with seasonal regularity in areas with a wet season. Observations of seasonal, near-exclusive insectivory have been made for blue-throated hummingbirds, as well as swallow-tailed hummingbirds in an urban park in Brazil. Other studies report 70–100% of feeding time devoted to arthropods; As their nestlings consume only arthropods, and possibly because their own requirements increase, breeding females spend 3–4 times as long as males foraging for arthropods, although 65–70% of their feeding time is still devoted to nectar. while the purple-throated carib has been reported to spend <1% of time consuming insects in Dominica. Hummingbirds digest their food rapidly due to their small size and high metabolism; a mean retention time less than an hour has been reported. Hummingbirds spend an average of 20% of their time feeding and 75–80% sitting and digesting.
Because their high metabolism makes them vulnerable to starvation, hummingbirds are highly attuned to food sources. Some species, including many found in North America, are territorial and try to guard food sources (such as a feeder) against other hummingbirds, attempting to ensure a future food supply.