The swift is a small bird that is known for its speed and aerial maneuverability. Despite its name, the swift is not actually related to fish at all – it is a bird species that belongs to the Apodiformes order. So while it may seem confusing due to the word “swift” being in the name, a swift is definitely a bird and not a fish.
What are the characteristics of swifts that identify them as birds?
There are several key characteristics of swifts that clearly identify them as birds rather than fish:
- Swifts have feathers – Feathers are a defining feature of birds. Fish have scales rather than feathers.
- Swifts have wings – The wings of swifts allow them to fly swiftly through the air. Fish have fins rather than wings.
- Swifts have hollow bones – Like other birds, swifts have lightweight, hollow bones which aid in flight. Fish bones are solid rather than hollow.
- Swifts build nests – Swifts build nests out of twigs, leaves, feathers, moss, etc. Fish do not build nests to lay eggs.
- Swifts lay eggs – Female swifts lay eggs and incubate them until hatching. Fish reproduce by laying eggs that are fertilized externally in water.
- Swifts breathe air – Swifts have lungs and breathe air. Fish have gills and breathe underwater.
- Swifts are terrestrial – Swifts walk and perch on branches and cliffs. Fish live fully aquatic lives underwater.
So while the name “swift” might evoke thoughts of a quick fish or other aquatic animal, swifts share all the major characteristics of birds when it comes to their anatomy, reproduction, and habitat. The similarities between swifts and fish are limited to superficial traits like speed.
What types of swifts are there?
There are around 90 known species of swifts in the Apodidae family. Some of the major types of swifts include:
- Chimney swift – Found in North America, chimney swifts nest in old chimneys or tree hollows.
- Common swift – The most widespread swift species, found throughout Europe and Asia.
- White-throated needletail – Native to Asia and Australasia, these swifts are known for their distinctive sharp tails.
- Alpine swift – Breeding across mountain ranges in Europe and Asia, they nest on cliffs and rock faces.
- White-rumped swift – Found in Africa, India, and southeast Asia with white patches on their rumps.
- Pacific swift – Occurs along the northwest Pacific coast of North America.
There are also swifts with very limited ranges like the Seychelles swift found only in the Seychelles islands and the scarcer swift endemic to the Philippines.
What is the swift’s habitat and behavior like?
Swifts are found worldwide on every continent except Antarctica. They occur in a variety of habitats from woodlands to mountains to urban areas. What all swifts’ habitats have in common is areas where the swifts can find suitable nesting sites and catch flying insects while in flight.
Some key facts about swifts’ habitats and behavior include:
- Nesting – Swifts nest inside chimneys, hollow trees, caves, crevices in cliffs, and buildings.
- Foraging – Swifts catch insects like flies, aphids, beetles, winged ants, and mosquitoes while in flight.
- Migration – Many swifts migrate long distances, like from North America to Peru.
- Flight – Swifts fly nearly constantly, even sleeping on the wing by gliding for long periods.
- Speed – Swifts can reach speeds over 100 mph in flight and are amongst the fastest birds.
- Agility – Their slender, curved wings allow incredible aerial agility and maneuvering.
- Gregarious – Swifts form large flocks, especially during migration and when nesting.
Overall, swifts are highly aerial, agile fliers that live life on the wing. Their evolution is intimately connected to their life in the air.
How do swifts reproduce and raise young?
Swifts share the key reproductive traits of other birds when it comes to breeding:
- Mating – Swifts form monogamous pair bonds for breeding. Courtship often occurs on the wing.
- Nesting – Nests are often reused for many years and reinforced with saliva.
- Eggs – The female swift lays a clutch of 2-7 white eggs depending on species.
- Incubation – Both parents incubate the eggs for around 3 weeks before hatching.
- Chicks – The altricial chicks are born helpless, with closed eyes and no down.
- Fledging – Chicks leave the nest for their first flight at 6-8 weeks old.
- Care – The parents continue to care for the fledglings, feeding them in flight.
Like all bird species, swifts reproduce via egg laying rather than the underwater spawning that fish do. The parents actively incubate the eggs and raise the chicks until fledging.
How did swifts evolve to be such aerial masters?
Swifts are sometimes described as “flying cigars” due to their superb aerial abilities. Several key adaptations have evolved that allow swifts to be such aerial masters:
- Wings – Their long, narrow, curved wings enable high-speed flight and quick maneuvers.
- Flight muscles – Swifts have large pectoral muscles for powering flight attached to an enlarged sternum.
- Lightweight – With tiny legs and feet, swifts are highly optimized for flight and very lightweight.
- Metabolism – They have high metabolisms even at rest to provide energy for nearly constant flying.
- Vision – Swifts have excellent vision adapted for catching fast-flying insects.
- Maneuverability – Their short tail and wings positioned far back aid tight turns and acrobatics.
Millions of years of evolution to catch aerial prey mid-flight led to these adaptations that make swifts such agile fliers today.
How can you identify a swift?
Identifying swifts can sometimes be tricky due to their speed and high-flying habits. However, there are some key identification points to look for:
- Silhouette – Look for a cigar or missile-shaped silhouette with long, scythe-like wings.
- Size – Swifts are small birds, ranging from 3.5-8.5 inches in length depending on species.
- Color – Often dark brown, black, or gray with lighter throat patches; some have white patches on rumps or bellies.
- Flight – Watch for high speed, continuous flight low over fields, marshes, lakes, and rivers as they hunt.
- Calls – Listen for their high-pitched, twittering or screaming calls, especially around nesting colonies.
- Nests – Look for nest sites such as chimneys or hollow trees with swift activity.
Taking note of these identification points will help distinguish swifts from similar birds like swallows or falcons.
Why are swifts sometimes considered aerial ‘sea mammals’?
Some ornithologists have drawn comparisons between swifts living an almost entirely aerial life and marine mammals adapted to life in the sea. Just as whales and dolphins evolved for aquatic life, swifts evolved as aerial specialists.
Similarities that lead to the sea mammal comparison include:
- Spending virtually all their lives airborne.
- Covering huge distances constantly on the wing.
- Foraging for food in flight as they travel.
- Migrating enormous distances seasonally.
- Roosting and sleeping on the wing or water surface.
- Raising young in nesting colonies.
- Streamlined bodies adapted for their fluid environment.
Of course swifts and sea mammals have many differences too in terms of anatomy, locomotion, respiration, and more. But their evolution in adapting fully to life in their respective fluid, 3D environments show some noteworthy parallels.
Conclusion
In summary, swifts demonstrate through their anatomy, behavior, reproduction, and evolution that they are unquestionably birds rather than fish or any other type of animal. Their mastery of flight sets them apart from all other birds and gives insight into aerial adaptation. So next time you see a swift rapidly zooming overhead, you can appreciate it as a consummate avian flier rather than some kind of airborne fish.