Hummingbirds belong to the taxonomic order Apodiformes. Apodiformes is an order of highly specialized birds including swifts and hummingbirds that is part of the class Aves. Here are some key facts about the taxonomic order of hummingbirds:
Hummingbirds are unique and fascinating birds that have captivated humans for centuries with their beauty and speedy flight. They are known for their ability to hover in midair and fly backwards and upside down, feats made possible by specialized wings that flap up to 80 times per second. Hummingbirds have the highest metabolism of any homeothermic animal, requiring frequent feeding on floral nectar. There are over 300 different species of hummingbirds spread across the Americas from Alaska to Chile, displaying incredible diversity in size, color, behavior, habitat, and adaptation. Understanding where hummingbirds fall within the taxonomic classification system provides deeper insight into their evolutionary history and relationship to other bird groups.
Taxonomic Order
The taxonomic order to which hummingbirds belong is called Apodiformes. Apodiformes is part of the larger clade Calledinia in the class Aves, which includes all birds. There are approximately 450 species of birds in the order Apodiformes, divided into three families:
- Trochilidae – hummingbirds
- Hemiprocnidae – tree swifts
- Apodidae – swifts
Some key features that unite the Apodiformes order include:
- Small to medium sized birds with long, curved bills
- Short legs with very reduced feet adapted for perching rather than walking
- Long, pointed wings for agile flight
- Vision adapted for speed and precision in flight
- Highly aerial – spend majority of life flying rather than on ground
- Feed while hovering in midair
- Unique toe orientation – three toes face forward, one faces backward
The hummingbirds make up the Trochilidae family, which includes all hummingbird species. The other two families consist of swifts and tree swifts. While swifts share some common traits with hummingbirds, they also differ in a few key ways:
| Trait | Hummingbirds | Swifts |
|---|---|---|
| Bill shape | Long, slender, slightly curved | Short, wide, less curved |
| Wings | Small, designed for hovering | Long, scythe-shaped for fast flight |
| Color | Iridescent, colorful | Generally dark, drab colors |
| Vocalizations | Squeaks, chirps | Screeches, chatter |
Distinguishing Features of Hummingbirds
Hummingbirds have numerous unique adaptations that differentiate them from other Apodiformes and aid their nectar-feeding lifestyle:
- Bill – Long and slender to access nectar deep within flowers. Some species have curved or decurved bills specialized for certain flower shapes.
- Tongue – Long, extendable tongues with forked tips to lap up nectar.
- Wings – Small, compact wings that beat 15-80 times per second, enabling hummingbirds to hover and fly in any direction.
- Metabolism – Extremely high metabolism requiring large amounts of energy from nectar. Hummingbirds eat up to 2-3 times their body weight in nectar each day.
- Feet – Small, weak feet used only for perching, not walking or hopping.
- Plumage – Iridescent, metallic feather colors that shimmer and change hue in light. Males are more colorful than females.
- Size – The smallest birds in the world, ranging from 2-8 inches long and 2-20 grams in weight.
Unique adaptations in hummingbirds’ circulatory and respiratory systems allow them to meet their sky-high metabolic demands. They have proportionately larger hearts and higher red blood cell counts than other birds. Their rapid breathing and oxygen consumption during flight necessitate an enlarged heart, increased lung capacity, and more capillaries feeding the tissues.
Evolutionary History
The evolutionary history of hummingbirds reaches back 30-40 million years to the early Oligocene period. The earliest hummingbird fossils indicate they originated in South America, which served as the ancestral homeland to all modern hummingbird species. By about 22 million years ago in the early Miocene, the main hummingbird groups began splitting into the specialized forms we see today such as hermits, mangoes, coquettes, and mountain gems. Key milestones in hummingbird evolutionary history include:
- ~30-40 million years ago – Earliest hummingbird-like fossils appear in South America. Hummingbirds diverge evolutionarily from swifts.
- 25 million years ago – Ancestors of modern hummingbirds emerge; rapid diversification begins.
- 10 million years ago – Bee hummingbirds, the smallest species today, appear in the fossil record.
- 3 million years ago – Andes mountains uplift leads to more specialized hummingbird species.
- 1 million years ago – Hummingbirds disperse to North America via the Panamanian land bridge.
- Present day – Rapid speciation continues, with new hummingbird species still being discovered.
The hummingbird family has diverged into around 140 different genera over the course of its evolution. DNA evidence shows nine main clades or branches within the Trochilidae family:
- Topazes
- Hermits
- Mangoes
- Coquettes
- Brilliants
- Patagona (giant hummingbird)
- Mountain gems
- Bees
- Emeralds
Each branch has evolved distinct traits related to body size, bill shape, plumage, habitat, courtship displays, and more. For example, Topazes consist of larger hummingbirds adapted to more temperate climates, while Bees contain the smallest hummingbird species specialized for high-altitude Andean habitats. Continued evolution has led to a dazzling diversity of hummingbirds occupying many ecological niches in the Americas.
Phylogenetic Relationships
Phylogenetic analysis shows that hummingbirds cluster into two main clades within the Apodiformes order: Phaethornithinae (hermits) and Trochilinae (all other hummingbirds). Molecular studies indicate hummingbirds are most closely related evolutionarily to swifts, with whom they diverged approximately 42 million years ago likely due to differences in feeding strategies. Together, hummingbirds and swifts comprise the suborder Apodi. Some other discoveries about the phylogenetic relationships among hummingbird groups include:
- Hermits are the earliest branching lineage of hummingbirds, splitting from other hummingbirds ~22 million years ago.
- The genera Eutoxeres (sicklebills) and Androdon (tooth-billed hummingbird) represent ancient and unique evolutionary lineages.
- The bee hummingbirds of South America and North American ruby-throated hummingbird represent some of the most recently evolved species.
- Physical attributes like bill length and wing shape correspond closely with genetic phylogenetic branching patterns.
- Island species like those in the Caribbean diversified rapidly and recently from South American ancestors.
Understanding the evolutionary relationships among hummingbird groups helps explain their biogeography across the Americas. Research into hummingbird phylogenetics also informs taxonomy, conservation priorities, and our knowledge about how unique adaptations have arisen over time.
Current Taxonomy
The current taxonomy of hummingbirds categorizes them into the following hierarchical classifications from most broad to most specific:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves – birds
- Order: Apodiformes
- Family: Trochilidae – hummingbirds
- Subfamilies: Phaethornithinae, Trochilinae
- Tribes: Hermits, Mangoes, Brilliants, Coquettes, etc.
- Genera: 141 recognized genera, including Amazilia, Archilochus, Atthis, etc.
- Species: ~343 currently recognized species, with new species still being discovered periodically
Within the hummingbird family Trochilidae, morphological and molecular research has helped scientists classify genera and species more accurately. However, the classification of hummingbirds is still being refined as new phylogenetic research emerges. The number of recognized genera has expanded greatly in recent decades. Ongoing study of hummingbird DNA, fossils, ecology, and biogeography continues to provide new insight into the evolutionary relationships and taxonomy of these spectacular birds.
Hummingbird Conservation
While most hummingbird species are currently thriving, habitat loss poses increasing threats to some specialized or endangered hummingbirds. Conservation priorities for hummingbirds include:
- Protecting critical stopover habitats during migration
- Maintaining flowering plants and nectar corridors
- Safeguarding high Andean cloud forest and paramo grassland habitats
- Creating backyard habitats with native plants and fresh water
- Addressing climate change impacts on delicate ecosystems
- Monitoring effects of pesticides and insect population declines
- Educating the public to support and engage in conservation
Some endangered hummingbirds like the Esmeraldas Woodstar of Ecuador or Juan Fernandez Firecrown of Chile require targeted efforts to save remaining habitat and breeding areas. Broad initiatives to conserve tropical forests and South American wilderness also promise protection for numerous hummingbird species at risk. Responsible ecotourism can boost enthusiasm for hummingbirds while funding conservation. Continued research and monitoring of hummingbird populations informs protective policies and status assessments for threatened species. Given their appeal and ecological importance, hummingbirds warrant significant conservation attention to preserve the diversity and beauty of these unique birds.
Conclusion
Hummingbirds are captivating exemplars of nature’s ingenuity, exhibiting a cornucopia of evolutionary innovations allowing them to flourish across varied environments. Understanding their taxonomic order Apodiformes provides a window into their ancestry, adaptive radiation, and relationship to swifts. While integral parts of New World ecosystems, hummingbirds still require diligent conservation amid increasing threats. These tiny dynamos will continue inspiring both scientific curiosity and widespread affection with their spectacular flying abilities, rainbow plumage, and energetic lifestyles. Ensuring hummingbirds thrive in coming decades will require greater understanding of their taxonomy alongside dedicated environmental stewardship at all levels.
