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96-794: Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae . With approximately 366 species and 113 genera , they occur from Alaska to Tierra del Fuego , but most species are found in Central and South America . As of 2024, 21 hummingbird species are listed as endangered or critically endangered , with numerous 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

192-604: A museum drawer in Stuttgart ; they had been unearthed in a clay pit at Wiesloch –Frauenweiler, south of Heidelberg , Germany , and, because hummingbirds were assumed to have never occurred outside the Americas, were not recognized to be hummingbirds until Mayr took a closer look at them. Fossils of birds not clearly assignable to either hummingbirds or a related extinct family, the Jungornithidae, have been found at

288-501: A behaviour known as "stropping". Penguins use their whole heads to stroke, in a motion referred to as "wiping". Birds regularly fluff up their plumage and repeatedly shake their bodies while preening. Experiments have shown that the shaking action can "rezip" a majority of split feather barbules. Birds cannot use their beaks to apply preen oil to their own heads. Instead, many use their feet in an action called scratch-preening. Once they have gathered preen oil on their beak, they scrape

384-794: A better sense of smell. A third stage of bird evolution starting with Ornithothoraces (the "bird-chested" avialans) can be associated with the refining of aerodynamics and flight capabilities, and the loss or co-ossification of several skeletal features. Particularly significant are the development of an enlarged, keeled sternum and the alula , and the loss of grasping hands. † Anchiornis † Archaeopteryx † Xiaotingia † Rahonavis † Jeholornis † Jixiangornis † Balaur † Zhongjianornis † Sapeornis † Confuciusornithiformes † Protopteryx † Pengornis Ornithothoraces † Enantiornithes Preening Over time, some elements of preening have evolved to have secondary functions. Ritualised preening has become

480-512: A bird to pathogens. There is evidence that water-borne avian influenza virus is "captured" by the preen oil on feathers, providing a possible route for infection. The ingestion of parasites during preening may result in infection; the tick-borne disease louping ill virus can be transmitted to red grouse if the bird consumes a tick carrying the disease. Caged birds , particularly parrots, sometimes overpreen in response to being exposed to strong scents (such as nicotine or air fresheners) or as

576-534: A bird with a dominant or aggressive cage mate. The use of the word preen to mean the tidying of a bird's feathers dates from Late Middle English . It appears to be a variant of the word prune ; one now-obsolete definition of prune meant "anoint", based on the Latin ungere , which had the same meaning. This usage was combined with the Scottish and northern English dialect preen meaning "pierce" or "pin", due to

672-471: A bird's feathers. One study of Eurasian hoopoes showed that the presence of symbiotic bacteria ( Enterococcus faecalis ) in their preen oil inhibited the growth of the feather-degrading bacteria Bacillus licheniformis . Enterococcus faecalis did this by releasing a bacteriocin . Female hoopoes transfer preen oil onto their brood patches and eggs, which results in the transfer of bacteria as well. Preen oil and bacteria are rubbed into microscopic pits on

768-473: A definition similar to "all theropods closer to birds than to Deinonychus ", with Troodon being sometimes added as a second external specifier in case it is closer to birds than to Deinonychus . Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and

864-463: A female at speeds around 23 m/s (83 km/h; 51 mph). The sexes differ in feather coloration, with males having distinct brilliance and ornamentation of head, neck, wing, and breast feathers. The most typical feather ornament in males is the gorget – a bib-like iridescent neck-feather patch that changes brilliance with the viewing angle to attract females and warn male competitors away from territory. Hummingbirds begin mating when they are

960-413: A few parrots and pigeons . Some species that lack a preen gland instead have powder down feathers which continually break down into a fine dust that the birds apply to their contour feathers while preening. These powder down feathers may be scattered throughout the bird's plumage or concentrated into dense patches. As well as helping to waterproof and preserve the bird's feathers, powder down can give

1056-439: A flocking species with a complex hierarchy, show similar frequencies of initiating and reciprocating allopreening of the head and neck regardless of social status, time of year or group size, which suggests that such activity is primarily related to feather hygiene. Most allopreening is done between the two members of a mated pair, and the activity appears to play an important role in strengthening and maintaining pair bonds . It

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1152-590: A foot across their bill to transfer the oil, and then scratch the oil into the feathers on their head. Longer-necked birds may rub their head directly on their uropygial gland. Some species (including nightjars , herons , frigatebirds , owls and pratincoles ) have comb-like serrations on the claw (a pectinate claw) of the middle toe which may aid in scratch-preening. Some species stretch their leg over their lowered wing to reach their head (known as "indirect" scratching), while others extend their leg between their wing and their body (known as "direct" scratching). There

1248-484: A full clutch of eggs (by the removal of eggs from their nest) responded by preening and nest building – both displacement activities. When all three eggs in their regular clutch were removed, the gulls showed a significant increase in the amount of time they spent preening. The conflict between two incompatible drives, such as incubating and escape, can lead a bird to engage in displacement activities. Nesting Sandwich and common terns preen when they have been alarmed by

1344-507: A great deal of time maintaining them. When resting, birds may preen at least once an hour. Studies on multiple species have shown that they spend an average of more than 9% of each day on maintenance behaviours, preening occupying over 92% of that time, though this figure can be significantly higher. Studies found that some gull species spent 15% of daylight hours during the breeding season preening, while another showed that common loons spent upwards of 25% of their day preening. In most of

1440-442: A group called Paraves . Some basal members of Deinonychosauria, such as Microraptor , have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal , have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that

1536-638: A high metabolic rate dependent on foraging for sugars from flower nectar. Hummingbird legs are short with feet having three toes pointing forward and one backward – the hallux . The toes of hummingbirds are formed as claws with ridged inner surfaces to aid gripping onto flower stems or petals. Hummingbirds do not walk on the ground or hop like most birds, but rather shuffle laterally and use their feet to grip while perching, preening feathers, or nest-building (by females), and during fights to grab feathers of opponents. Hummingbirds apply their legs as pistons for generating thrust upon taking flight, although

1632-427: A high proportion of sucrose , whereas insect-pollinated flowers typically produce more concentrated nectars dominated by fructose and glucose . Bird Birds are a group of warm-blooded vertebrates constituting the class Aves ( Latin: [ˈaveːs] ), characterised by feathers , toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart , and

1728-453: A metallic sheen to the plumage. A bird's plumage is primarily made up of two feather types: firm vaned or pennaceous feathers on the surface, with softer down feathers underneath. Both feather types have a central shaft with narrower barbs branching from that shaft. Pennaceous feathers also have much smaller barbules branching from the entire length of each barb; these barbules have tiny hooks along their length, which interlock with

1824-428: A part in protecting at least some species from some internal parasites; a study of the incidence of avian malaria in house sparrows found that uninfected birds had larger uropygial glands and higher antimicrobial activity in those glands than infected birds did. There is even evidence that the foul-smelling preen oil of hoopoes and wood hoopoes may help to repel mammalian predators . Preen oil helps to maintain

1920-466: A part of some courtship displays , for example. It is also a displacement activity that can occur when birds are subjected to two conflicting drives. Though primarily an individual function, preening can be a social activity involving two or more birds – a behaviour known as allopreening. In general, allopreening occurs either between two members of a mated pair or between flock members in a social species. Such behaviour may assist in effective grooming, in

2016-474: A pink flush to the bird's plumage. The preen oil of several gull and tern species, including Ross's gull , contains a pink colourant which does the same. The heads of these birds typically show little pink, because of the difficulty of reaching those areas with preen oil. The yellow feathers of the great hornbill are also cosmetically coloured during preening. The preen oil of the Bohemian waxwing increases

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2112-491: A poor job overall as a result. Displaced feathers can cause birds considerable trouble; such feathers might become damaged, could interrupt the smooth flow of air over a flying bird, or might allow the bird's body heat to escape. Preening allows a bird to reposition such displaced feathers. There is evidence that filoplumes , specialised feathers buried under a bird's outer covering of contour feathers , help to signal when contour feathers have been displaced. Mechanoreceptors at

2208-416: A potential predator or when they have had an aggressive encounter with a neighbouring bird, for instance. Fighting European starlings will break off their battles to preen. Although preening is primarily an individual behaviour, some species indulge in allopreening, one individual preening another. It is not particularly common among birds, though species from at least 43 families are known to engage in

2304-406: A sister group, the order Crocodilia , contain the only living representatives of the reptile clade Archosauria . During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica . However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and

2400-543: A slight overhang at the tip of their upper mandible. Experiments suggest that this allows birds to apply shearing forces that kill the flat-bodied feather lice ; the removal of the bill tip caused an increase in feather lice due to ineffective preening. Preening is often done in association with other maintenance behaviours, including bathing, dusting , sunning, oiling or anting , and can either precede or follow these other behaviours. All birds typically preen after bathing. Groups of birds sometimes all groom individually at

2496-441: A small number of flower species. Even in the most specialized hummingbird–plant mutualisms, the number of food plant lineages of the individual hummingbird species increases with time. 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

2592-466: A state similar to hibernation , and slow their metabolic rate to 1 ⁄ 15 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 3,900 miles (6,300 km). Hummingbirds split from their sister group , the swifts and treeswifts , around 42 million years ago. The oldest known fossil hummingbird

2688-424: A strong yet lightweight skeleton . Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich . There are over 11,000 living species and they are split into 44 orders . More than half are passerine or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are

2784-717: A time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction . They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds , parrots, and other species are popular as pets. Guano (bird excrement)

2880-402: A year old. Sex occurs over 3–5 seconds when the male joins its cloaca with the female's, passing sperm to fertilize the female's eggs. Hummingbird females build a nest resembling a small cup about 1.5 inches (3.8 cm) in diameter, commonly attached to a tree branch using spider webs, lichens , moss, and loose strings of plant fibers (image). Typically, two pea -shaped white eggs (image) –

2976-773: Is Eurotrochilus , from the Rupelian Stage of Early Oligocene Europe. Hummingbirds are the smallest known and smallest living avian theropod dinosaurs . 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 . Across the estimated 366 species, hummingbird weights range from as small as 2 grams (0.071 oz) to as large as 20 grams (0.71 oz). They have characteristic long, narrow beaks (bills) which may be straight (of varying lengths) or highly curved. The bee hummingbird – only 6 centimetres (2.4 in) long and weighing about 2 grams (0.071 oz) –

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3072-540: Is called ornithology . Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs . Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians . Birds are descendants of the primitive avialans (whose members include Archaeopteryx ) which first appeared during the Late Jurassic . According to recent estimates, modern birds ( Neornithes ) evolved in

3168-790: Is due to convergent evolution . 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. Hummingbirds are restricted to the Americas from south central Alaska to Tierra del Fuego , including the Caribbean. The majority of species occur in tropical and subtropical Central and South America, but several species also breed in temperate climates and some hillstars occur even in alpine Andean highlands at altitudes up to 5,200 m (17,100 ft). The greatest species richness

3264-452: Is generally larger (in relation to body size) in waterbirds, including terns , grebes and petrels. However, studies have found no clear correlation between the size of the gland and the amount of time a species spends in the water; it is not consistently largest in those species that spend the most time in the water. Preen oil plays a role in reducing the presence of parasitic organisms, such as feather-degrading bacteria, lice and fungi, on

3360-417: Is greatest, possible ancestors of extant hummingbirds may have lived in parts of Europe and what is southern Russia today. As of 2023, 366 hummingbird species have been identified. They have been traditionally divided into two subfamilies : the hermits (subfamily Phaethornithinae) and the typical hummingbirds (subfamily Trochilinae , all the others). Molecular phylogenetic studies have shown, though, that

3456-429: Is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds

3552-610: 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. While fewer than 25 different species of hummingbirds have been recorded from the United States and fewer than 10 from Canada and Chile each, Colombia alone has more than 160 and

3648-475: Is more common in species where both parents help to raise the offspring and correlates with an increased likelihood that partners will remain together for successive breeding seasons. Allopreening often features as part of the "greeting ceremony" between the members of a pair in species such as albatrosses and penguins, where partners may be separated for a relatively long period of time, and is far more common among sexually monomorphic species (that is, species where

3744-503: Is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. Over 40% of key traits found in modern birds evolved during the 60 million year transition from the earliest bird-line archosaurs to the first maniraptoromorphs , i.e. the first dinosaurs closer to living birds than to Tyrannosaurus rex . The loss of osteoderms otherwise common in archosaurs and acquisition of primitive feathers might have occurred early during this phase. After

3840-438: Is only reciprocal when done between members of a mated pair; otherwise, the dominant bird reciprocates in fewer than 10% of the instances. If birds are exposed to some pollutants , such as leaking petroleum , they can quickly lose the preen oil from their feathers. This causes a loss of heat regulation and waterproofing, and rapidly leads to the bird becoming chilled. If waterbirds are exposed, they can lose both buoyancy and

3936-435: Is showing, then will place their bill behind the speculum as if preening it. Courtship preening is more conspicuous than is preening for feather maintenance, using more stereotypical movements. Preening may be performed as a displacement activity . In some cases, it is done in place of another activity that birds are strongly motivated, but unable, to do. In one study, black-headed gulls which were prevented from incubating

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4032-644: Is some evidence that allopreening may help to keep in good condition those feathers that a bird cannot easily reach by itself; allopreening activities tend to focus on the head and neck. It may also help to remove ectoparasites from those hard-to-reach areas. Allopreening is most common among species that are regularly in close physical contact due to flocking or social behaviours, where such contact allows for easier transfer of ectoparasites between individuals. In one study, Macaroni penguins that frequently allopreened had significantly fewer ticks on their heads and necks than those that did not. Green wood hoopoes ,

4128-488: Is some evidence that the method used by a species may be related to its ecology. For instance, New World warblers that are primarily arboreal tend to be overwing scratchers, while those that spend significant time on the ground are typically underwing scratchers. In general, preening takes place while the bird is perched, on the ground, or swimming, but some of the more aerial species (including swifts , swallows , terns and albatrosses ) preen while flying. Many birds have

4224-516: Is synonymous to Avifilopluma. † Scansoriopterygidae † Eosinopteryx † Jinfengopteryx † Aurornis † Dromaeosauridae † Troodontidae Avialae Based on fossil and biological evidence, most scientists accept that birds are a specialised subgroup of theropod dinosaurs and, more specifically, members of Maniraptora , a group of theropods which includes dromaeosaurids and oviraptorosaurs , among others. As scientists have discovered more theropods closely related to birds,

4320-405: Is the one used most often; it is more effective than stroking for applying preen oil, removing ectoparasites , rejoining unzipped barbules, and rearranging feathers. The stroking action is typically done in the direction the feathers lie, with the bill either opened or closed. Stroking is used to apply preen oil, as well as to dry and smooth plumage. Grebes stroke more vigorously with an open bill –

4416-537: Is the world's smallest bird and smallest warm-blooded vertebrate . Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling helicopter -like flight in any direction, including the ability to hover. Particularly while hovering, the wing beats produce the humming sounds, which function to alert other birds. In some species, the tail feathers produce sounds used by males during courtship flying. Hummingbirds have extremely rapid wing-beats as high as 80 per second, supported by

4512-535: Is used by many scientists including adherents to the PhyloCode . Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils , and assigning them, instead, to the broader group Avialae, on the principle that a clade based on extant species should be limited to those extant species and their closest extinct relatives. Gauthier and de Queiroz identified four different definitions for

4608-403: Is vital that birds have some way to protect and lubricate them. Otherwise, age and exposure cause them to become brittle. To facilitate that care, many bird species have a preen or uropygial gland , which opens above the base of the tail feathers and secretes a substance containing fatty acids, water, and waxes. The bird gathers this substance on its bill and applies it to its feathers. The gland

4704-626: The Brace's emerald ( Riccordia bracei ) and Caribbean emerald ( Riccordia elegans ) – have been declared extinct . Of the 15 species of North American hummingbirds that inhabit the United States and Canada, several have changed their range of distribution, while others showed declines in numbers since the 1970s, including in 2023 with dozens of hummingbird species in decline. As of the 21st century, rufous, Costa's, calliope, broad-tailed, and Allen's hummingbirds are in significant decline, some losing as much as 67% of their numbers since 1970 at nearly double

4800-722: The Late Cretaceous and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non- ornithuran dinosaurs. Many social species preserve knowledge across generations ( culture ). Birds are social, communicating with visual signals, calls, and songs , and participating in such behaviour as cooperative breeding and hunting, flocking , and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous , usually for one breeding season at

4896-510: 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

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4992-669: The Tiaojishan Formation of China, which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi , Xiaotingia zhengi , and Aurornis xui . The well-known probable early avialan, Archaeopteryx , dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds but were later lost during bird evolution. These features include enlarged claws on

5088-454: 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 . 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. Hummingbirds remain in dynamic diversification inhabiting ecological regions across South America, North America, and

5184-409: The ornithophilous flowers upon which they feed. This coevolution implies that morphological traits of hummingbirds, such as bill length, bill curvature, and body mass, are correlated with morphological traits of plants, such as corolla length, curvature, and volume. Some species, especially those with unusual bill shapes, such as the sword-billed hummingbird and the sicklebills , are coevolved with

5280-465: The "pricking" action of the bird's beak during preening. Preening is a maintenance behaviour used by all birds to care for their feathers. It is an innate behaviour; birds are born knowing the basics, but there is a learned component. Birds that are hand-reared without access to a role model have abnormalities in their preening behaviours. Despite spending considerable time in their efforts, they do not use proper techniques to groom effectively and may do

5376-454: The Caribbean, indicating an enlarging evolutionary radiation . Within the same geographic region, hummingbird clades coevolved with nectar-bearing plant clades, affecting mechanisms of pollination . 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 ). Hummingbirds are specialized nectarivores tied to

5472-558: The English names are those introduced in 1997. The scientific names are those introduced in 2013. Florisuginae – topazes Phaethornithinae – hermits Polytminae – mangoes Heliantheini – brilliants Lesbiini – coquettes Patagoninae – giants Lampornithini – mountain gems Mellisugini – bees Trochilini – emeralds While all hummingbirds depend on flower nectar to fuel their high metabolisms and hovering flight, coordinated changes in flower and bill shape stimulated

5568-472: The UV reflectance of its feathers. Ritualised preening is used in courtship displays by several species, particularly ducks; such preening is typically designed to draw attention to a modified structure (such as the sail-shaped secondaries of the drake mandarin duck ) or distinctive colour (such as the speculum ) on the bird. Mallards of both sexes will lift a wing so that the brightly coloured speculum

5664-719: The United States and Canada indicate that the ruby-throated hummingbird numbers are around 34 million, rufous hummingbirds are around 19 million, black-chinned , Anna's , and broad-tailed hummingbirds are about 8 million each, calliopes at 4 million, and Costa's and Allen's hummingbirds are around 2 million each. Several species exist only in the thousands or hundreds. According to the International Union for Conservation of Nature Red List of Threatened Species in 2024, 8 hummingbird species are classified as critically endangered , 13 are endangered , 13 are vulnerable , and 20 species are near-threatened . Two species –

5760-413: The ability to fly; this means they must swim constantly to stay warm and afloat (if they cannot reach land), and eventually die of exhaustion. While preening in an effort to clean themselves, they may ingest harmfully large amounts of the petroleum. Ingested oil can cause pneumonia , as well as liver and kidney damage. Studies done with black guillemots showed that even small amounts of ingested oil caused

5856-428: The appearance of Maniraptoromorpha, the next 40 million years marked a continuous reduction of body size and the accumulation of neotenic (juvenile-like) characteristics. Hypercarnivory became increasingly less common while braincases enlarged and forelimbs became longer. The integument evolved into complex, pennaceous feathers . The oldest known paravian (and probably the earliest avialan) fossils come from

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5952-451: The base of the filoplumes only fire when contour feathers are displaced or the filoplume moves. Preening enables birds to remove dirt and parasites from their plumage, and assists in the waterproofing of feathers. During moult , birds remove the sheaths from around their emerging pin feathers while preening. Because feathers are critical to a bird's survival – contributing to insulation, waterproofing and aerodynamic flight – birds spend

6048-665: The bee hummingbird to more successfully compete for flower foraging against insects. Many plants pollinated by hummingbirds produce flowers in shades of red, orange, and bright pink, although the birds take nectar from flowers of other colors. Hummingbirds can see wavelengths into the near- ultraviolet , but hummingbird-pollinated flowers do not reflect these wavelengths as many insect-pollinated flowers do. This narrow color spectrum may render hummingbird-pollinated flowers relatively inconspicuous to most insects, thereby reducing nectar robbing . Hummingbird-pollinated flowers also produce relatively weak nectar (averaging 25% sugars) containing

6144-452: The birds physiological distress. It interfered with the foraging efficiency of adults and decreased the growth rates of young birds. Allopreening may facilitate disease transmission between infected and non-infected individuals. West Nile virus has been found in the feather pulp of several species of corvid , for instance, meaning that birds that preen infected partners might become infected themselves. Even preening its own body may expose

6240-509: The birds that descended from them. Despite being currently one of the most widely used, the crown-group definition of Aves has been criticised by some researchers. Lee and Spencer (1997) argued that, contrary to what Gauthier defended, this definition would not increase the stability of the clade and the exact content of Aves will always be uncertain because any defined clade (either crown or not) will have few synapomorphies distinguishing it from its closest relatives. Their alternative definition

6336-749: The comparably small Ecuador has about 130 species. 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. Hummingbirds' 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

6432-665: The earliest members of Aves, is removed from this group, becoming a non-avian dinosaur instead. These proposals have been adopted by many researchers in the field of palaeontology and bird evolution , though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is often used synonymously with the vernacular term "bird" by these researchers. † Coelurus † Ornitholestes † Ornithomimosauria † Alvarezsauridae † Oviraptorosauria   Paraves Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used

6528-417: The earliest species of hummingbird occurred in the early Oligocene ( Rupelian about 34–28 million years ago) of Europe, belonging to the genus Eurotrochilus, having similar morphology to modern hummingbirds. 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. A map of

6624-483: The extinct moa and elephant birds . Wings, which are modified forelimbs , gave birds the ability to fly, although further evolution has led to the loss of flight in some birds , including ratites , penguins , and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds , have further evolved for swimming. The study of birds

6720-451: The first avialans were omnivores . The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It

6816-495: 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 . The hummingbird evolutionary tree shows that one key evolutionary factor appears to have been an altered taste receptor that enabled hummingbirds to seek nectar. Upon maturity, males of a particular species, Phaethornis longirostris,

6912-461: The hermits are sister to the topazes , making the former definition of the Trochilinae not monophyletic . The hummingbirds form nine major clades : the topazes and jacobins , the hermits, the mangoes , the coquettes , the brilliants , the giant hummingbird ( Patagona gigas ), the mountaingems , the bees , and the emeralds . The topazes and jacobins combined have the oldest split with

7008-431: The hooks of neighbouring barbules. Barbules can become unhooked as a result of a bird's daily activities – dislodged when the bird brushes up against vegetation, for instance, or when it interacts with another bird during fighting or mating. Preening may involve two kinds of bill actions: nibbling (or mandibulating) while working the feather from base to tip, or stroking with the bill either open or closed. The nibbling action

7104-453: 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 80 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 ,

7200-460: The hummingbird family tree – reconstructed from analysis of 284 species – shows rapid diversification from 22 million years ago. Hummingbirds fall into nine main 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. Molecular phylogenetic studies of

7296-572: The hummingbirds have shown that the family is composed of nine major clades. 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. In the cladogram below,

7392-785: The mutual activity. Most allopreening activity concentrates on the head and neck, a lesser amount being directed towards the breast and mantle and an even smaller percentage applied to the flanks . A few species are known to allopreen other areas, including the rump, tail, belly and underwing. Several hypotheses have been advanced to explain the behaviour: that it assists in effective grooming, that it assists in recognition of individuals (mates or potential sexual partners), and that it assists in social communication, reducing or redirecting potential aggressive tendencies. These functions are not mutually exclusive. Evidence suggests that different species may participate for different reasons, and that those reasons may change depending on

7488-402: The outermost half) can be seen in the evolution of maniraptoromorphs, and this process culminated in the appearance of the pygostyle , an ossification of fused tail vertebrae. In the late Cretaceous, about 100 million years ago, the ancestors of all modern birds evolved a more open pelvis, allowing them to lay larger eggs compared to body size. Around 95 million years ago, they evolved

7584-536: The previously clear distinction between non-birds and birds has become blurred. By the 2000s, discoveries in the Liaoning Province of northeast China, which demonstrated many small theropod feathered dinosaurs , contributed to this ambiguity. The consensus view in contemporary palaeontology is that the flying theropods, or avialans , are the closest relatives of the deinonychosaurs , which include dromaeosaurids and troodontids . Together, these form

7680-812: The rate of population loss over the previous 50 years. The ruby-throated hummingbird population – the most populous North American hummingbird – decreased by 17% over the early 21st century. Habitat loss, glass collisions, cat predation, pesticides , and possibly climate change affecting food availability, migration signals, and breeding are factors that may contribute to declining hummingbird numbers. By contrast, Anna's hummingbirds had large population growth at an accelerating rate since 2010, and expanded their range northward to reside year-round in cold winter climates. Some species of sunbirds — an Old World group restricted in distribution to Eurasia , Africa, and Australia — resemble hummingbirds in appearance and behavior, but are not related to hummingbirds, as their resemblance

7776-512: The recognition of individuals (mates or potential sexual partners), or in reducing or redirecting potential aggressive tendencies in social species. Most allopreening is confined to the head and neck, smaller efforts being directed towards other parts of the body. Ingestion of pollutants or disease-causing organisms during preening can lead to problems ranging from liver and kidney damage to pneumonia and disease transmission. Injury and infection can cause overpreening in caged birds, as can confining

7872-794: The rest of the hummingbirds. The hummingbird family has the third-greatest number of species of any bird family (after the tyrant flycatchers and the tanagers ). Fossil hummingbirds are known from the Pleistocene of Brazil and the Bahamas , but neither has yet been scientifically described, and fossils and subfossils of a few extant species are known. Until recently, older fossils had not been securely identifiable as those of hummingbirds. In 2004, Gerald Mayr identified two 30-million-year-old hummingbird fossils. The fossils of this primitive hummingbird species, named Eurotrochilus inexpectatus ("unexpected European hummingbird"), had been sitting in

7968-485: 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

8064-452: The same biological name "Aves", which is a problem. The authors proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below. They assigned other names to the other groups.   Lizards & snakes   Turtles   Crocodiles   Birds Under the fourth definition Archaeopteryx , traditionally considered one of

8160-451: The same time. This has been seen in species ranging from herons to blackbirds . Preening may help to send sexual signals to potential mates because plumage colouration (which can be altered by the act of preening) can reliably reflect the health or "quality" of its bearer. In some species, preen oil is used to cosmetically colour the plumage. During the breeding season, the preen oil of the great white pelican becomes red-orange, imparting

8256-628: The season and the individuals involved. In most cases, allopreening involves members of the same species, although some cases of interspecific allopreening are known; the vast majority of these involve icterids , though at least one instance of mutual grooming between a wild black vulture and a wild crested caracara has been documented. Birds seeking allopreening adopt specific, ritualised postures to signal so; they may fluff their feathers out or put their heads down. Captive birds of social species that normally live in flocks, such as parrots, will regularly solicit preening from their human owners. There

8352-551: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. Avialans diversified into a wide variety of forms during the Cretaceous period. Many groups retained primitive characteristics , such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). Increasingly stiff tails (especially

8448-1031: The sexes look outwardly similar). It appears to inhibit or redirect aggression, as it is typically the dominant bird that initiates the behaviour. Allopreening appears to reduce the incidence of conflict between members of some colonially living or colonially nesting species. Neighbouring common guillemots that engaged in allopreening were much less likely to fight. Since fights often lead to eggs or chicks being knocked off breeding cliffs, fewer fights led to greater breeding success for allopreening neighbours. Among social flocks of green wood hoopoes, rates of body allopreening (that is, allopreening of another bird's body rather than head and neck) increase with group size. Evidence suggests this type of allopreening reduces social tension, and thus plays an important role in group cohesion. More dominant birds receive far more body allopreening services than do lower-ranked birds, and lower-ranked birds initiate far more body allopreening bouts than do their higher-ranked flock mates. Body allopreening

8544-439: The shortness of their legs provides about 20% less propulsion than assessed in other birds. During flight, hummingbird feet are tucked up under the body, enabling optimal aerodynamics and maneuverability. Of those species that have been measured during flight, the top flight speeds of hummingbirds exceed 15 m/s (54 km/h; 34 mph). During courtship , some male species dive from 30 metres (100 ft) of height above

8640-549: The smallest of any bird – are incubated over 2–3 weeks in breeding season. Fed by regurgitation only from the mother, the chicks fledge about 3 weeks after hatching. The average lifespan of a ruby-throated hummingbird is estimated to be 3–5 years, with most deaths occurring in yearlings, although one banded ruby-throated hummingbird lived for 9 years and 2 months. Bee hummingbirds live 7–10 years. Although most hummingbird species live in remote habitats where their population numbers are difficult to assess, population studies in

8736-437: The studied species where the bird's sex could be determined in the field, males spent more time preening than females, though this was reversed in ducks. Some ratites , which are not dependent on their feathers for flight, spend far less time on maintenance behaviours. One study of ostriches found that they spent less than 1% of their time engaged in such behaviours. Fully grown feathers are essentially dead structures, so it

8832-424: The surface of the eggs during incubation . This alters the colour of the eggs (darkening them) but there is also evidence that the bacteria may help to protect the developing chicks. Other studies have shown that removing or restricting access to the uropygial gland typically results in a higher bacterial parasite load on the plumage, though not necessarily of feather-degrading bacterial species. Preen oil may play

8928-536: 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. Hummingbirds split from other members of Apodiformes, the insectivorous swifts (family Apodidae) and treeswifts (family Hemiprocnidae), about 42 million years ago, probably in Eurasia . Despite their current New World distribution,

9024-456: The waterproofing of a bird's plumage. Though the oil does not provide any direct waterproofing agent, it helps to extend the life of the feather – including the microscopic structures (the barbs and barbules) which interlock to create the waterproof barrier. While most species have a preen gland, the organ is missing in the ratites ( emu , ostriches, cassowaries , rheas and kiwis ) and some neognath birds, including bustards , woodpeckers ,

9120-573: The widest diversity of plumage color, particularly in blues, greens, and purples. Hummingbirds are the smallest mature birds, measuring 7.5–13 cm (3–5 in) in length. The smallest is the 5 cm (2.0 in) bee hummingbird , which weighs less than 2.0 g (0.07 oz), and the largest is the 23 cm (9 in) giant hummingbird , weighing 18–24 grams (0.63–0.85 oz). Noted for long beaks , hummingbirds are specialized for feeding on flower nectar , but all species also consume small insects. They are known as hummingbirds because of

9216-466: Was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae . Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use. Birds are categorised as the biological class Aves in Linnaean taxonomy . Phylogenetic taxonomy places Aves in the clade Theropoda as an infraclass or a subclass, more recently a subclass. Aves and

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