Hummingbirds are some of the most fascinating birds in the world. Known for their ability to hover in midair and fly backwards, they captivate people with their beauty and speedy flight. But where exactly do hummingbirds fit into the taxonomic classification system?
Hummingbirds belong to the family Trochilidae, which includes all 338 currently recognized hummingbird species. Trochilidae is part of the larger order Apodiformes, along with swifts and treeswifts. Apodiformes belongs to the class Aves, which contains all birds. Aves is within the phylum Chordata, which includes all vertebrates that possess a notochord and dorsal nerve cord at some point during development. Going up one more level, Chordata sits within the kingdom Animalia, which encompasses all animals.
To break it down:
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Aves |
| Order | Apodiformes |
| Family | Trochilidae |
Hummingbirds have a unique taxonomic classification that sets them apart from other types of birds and animals. In this article, we’ll take a closer look at each level of classification for hummingbirds, from kingdom down to genus and species. Understanding taxonomy provides insight into the evolutionary history and relationships between organisms like hummingbirds.
Kingdom Animalia
As members of the kingdom Animalia, hummingbirds belong to the broad group of multicellular, eukaryotic organisms that are heterotrophic, obtaining nutrition by ingesting other organisms. Animalia contains millions of species, from sponges to insects to mammals.
Some key characteristics of Animalia:
- Multicellular organization
- Eukaryotic cells with organelles like nuclei, mitochondria, golgi apparatus, and endoplasmic reticulum
- Lack cell walls
- Heterotrophic mode of nutrition
- Sexual and asexual reproduction
- Diploid life cycle with haploid gametes
Animals constitute one of the major kingdoms of life. Distinguishing features like complex body plans with differentiated tissues and organs, nervous system and sensory organs, and ability to move set them apart from plants, fungi, protists, archaea, and bacteria.
As birds, hummingbirds have all the characteristics of kingdom Animalia. Their bodies contain specialized tissues and organs. They consume energy and nutrients from floral nectar. And they reproduce sexually, with females laying fertilized eggs. This places hummingbirds firmly within this broad kingdom shared by all animals.
Phylum Chordata
Hummingbirds belong to the phylum Chordata, which includes all vertebrate animals. There are around 65,000 species in this phylum.
Chordates are characterized by:
- Presence of a notochord – a stiff, rod-shaped structure that provides support during embryonic development.
- Dorsal hollow nerve cord – forms the basis of the central nervous system.
- Pharyngeal gill slits – openings in the pharynx.
- Muscular tail – extends beyond the anus.
In vertebrates like hummingbirds, the notochord is replaced by the vertebral column or spine as development progresses. But its earlier presence is an important phylogenetic marker of the phylum.
The phylum Chordata contains three subphyla:
- Cephalochordata (lancelets)
- Urochordata (tunicates, salps, sea squirts)
- Vertebrata (vertebrates)
Hummingbirds belong to Vertebrata, along with fishes, amphibians, reptiles, birds, and mammals. Vertebrates possess a vertebral column and cranium.
Key features of vertebrates:
- Vertebral column
- Cranium that houses and protects the brain
- Well-developed brain
- Central and peripheral nervous systems
- Internal skeleton
- Endoskeleton made of bone or cartilage
- Parietal eye
As birds, hummingbirds exhibit all the standard vertebrate characteristics. Their spine provides structure and support. Their skull protects the brain. They have complex nervous systems and senses. This places hummingbirds solidly within the vertebrates.
Class Aves
Aves contains all birds, including the hummingbird. With approximately 10,000 living species, it is the most speciose class of tetrapod vertebrates.
Distinctive features of Aves:
- Feathers
- Toothless beaked jaws
- Hard-shelled eggs
- High metabolic rate
- Four-chambered hearts
- Lightweight skeletons
- Excellent vision
- Shelled eggs with large nutrient-rich yolks
- Small, light bodies due to fusion of certain bones
- Large pectoral muscles for flight
- Lungs with small openings and air sacs
- Hollow, pneumatic bones
Hummingbirds share all the standard bird adaptations like feathers, beaks, metabolically fast heart and respiration, and fused bones. Their small size, hover-feeding, and many other traits reveal further adaptations to their specific lifestyle and niche. But they belong firmly within the class containing all birds based on their underlying anatomy.
There are two groups within Aves that are distinguished mainly by anatomical differences:
1. Palaeognathae – flightless birds like ostriches, emus, kiwis
2. Neognathae – all other birds, including hummingbirds
Hummingbirds fall into the speciose Neognathae branch along with 95% of avian species.
Order Apodiformes
This order contains the swifts, treeswifts, and hummingbirds. There are around 450 species in Apodiformes. They are generally aerial foragers that catch insects on the wing.
Unique features of Apodiformes:
- Short legs adapted for clinging to vertical surfaces
- Weak feet with small muscles
- Wide gape
- Small reduced beak surrounded by bristles
- Short sturdy wings
- Long hand bones
- Short breastbone
- Fused wrist bones
- Long rigid shafts on outer wing feathers
These adaptations allow swifts, treeswifts, and hummingbirds to be agile, fast flyers that twist and turn adeptly in flight to catch insects. They spend most of their time flying, rather than perching or walking. Their short legs and feet are more adapted for clinging to surfaces.
Apodiformes contains three families:
- Hemiprocnidae (treeswifts)
- Apodidae (swifts)
- Trochilidae (hummingbirds)
Of these, Trochilidae is the largest family with over 300 species. Hummingbirds make up the bulk of this order. Their specialized adaptations, like hover-feeding and unique bill shapes, indicate they have diverged from their Apodiformes relatives to fill a distinct niche. But certain anatomical similarities, like short legs and aerial living, unite them with swifts and treeswifts in this order.
Family Trochilidae
Trochilidae is the family containing all extant hummingbirds. With over 300 described species, it is the second largest bird family after tyrant flycatchers.
Some common traits of Trochilidae:
- Small size and compact shape
- Short legs and feet
- Wings with ten primary feathers and nine secondaries
- Rapid wing beats up to 80 times per second
- Excellent maneuverability and ability to hover in place
- Slender bills adapted for accessing nectar
- Protractible tongues with forked tips for lapping up nectar
- High metabolism and rapid breathing
- Iridescent plumage
- Most species have brilliant, gaudy colors
- Sexual dimorphism in plumage – males are more colorful
- Complex courtship displays
- Polygynous mating systems
- Females build nests and provide parental care alone
These adaptations enable hummingbirds to hover near flowers while accessing nectar with their specialized bill and tongue. They beat their wings up to a hundred times per second during these hover-feeding bouts. Their small size helps them maneuver precisely in flight. And their rapid metabolism powers their unique lifestyle.
Within Trochilidae, there are several genera containing multiple species. For example:
- Archilochus – 4 species including the black-chinned hummingbird
- Calypte – 2 species including the Anna’s hummingbird
- Selasphorus – 5 species including the rufous hummingbird
- Eugenes – 23 species including the magnificent hummingbird
- Amazilia – 29 species including the buff-bellied hummingbird
Trochilidae contains essentially all modern hummingbirds on Earth today. They have evolved a range of anatomical and physiological adaptations that enable specialized nectarivory. Even their wing bone structure is uniquely adapted for complex hovering flight. This family includes some of the smallest birds and most acrobatic flyers on the planet.
Genus and Species
Within a genus, the final level of taxonomy is the individual species. There are over 300 recognized hummingbird species assigned to various genera of Trochilidae. Let’s look at one species as an example.
The rufous hummingbird (Selasphorus rufus) is a small hummingbird species found along the Pacific coast of North America. Some key identification features:
- Males have a bright orange-red throat and iridescent reddish-rose colored crown and back
- Females have green backs, white undersides with speckled throats
- Long, slender, slightly downcurved bill
- Males average 3-3.5 grams in weight, females 3-3.7 grams
- An average wingspan around 8-9 centimeters
This species breeds farther north than any other hummingbird. During migration, some individuals may travel over 3,000 miles between breeding and wintering grounds. Their diet consists of floral nectar, tree sap, and small insects like gnats and fruit flies.
The rufous hummingbird’s scientific name reveals its taxonomic classification:
- Selasphorus – the genus containing rufous hummingbirds and 4 other closely related species
- rufus – the specific epithet indicating this particular species
Together, the genus and unique species epithet give the formal binomial name that provides a precise taxonomic identifier. For the rufous hummingbird, that is Selasphorus rufus. This full scientific name denotes its unique place within the Trochilidae family tree.
Conclusion
Hummingbirds have a rich taxonomic history that places them in the phylum Chordata, class Aves, order Apodiformes, and family Trochilidae. Their distinguishing features, like rapid hover-feeding, indicate they form a special family within the order containing all swifts and hummingbirds.
Yet they share the standard bird adaptations of all species in class Aves. And their vertebrate characteristics link them to the broader phylum Chordata. Taxonomy reveals how hummingbirds are connected through evolution to other birds and organisms while still possessing unique traits and behaviors. Careful classification provides insight into the underlying connections and divergence of life on Earth.
