Swift (bird)

Swifts are birds that love to fly.

They are very fast in the air. Some can fly at high speeds. They catch bugs while they fly. This helps them stay full. Many swifts have tiny legs. They use their beaks to grab insects. Some swifts build nests with spit. They glue these nests to walls. Both parents help raise the babies. Swifts live on almost every land.

Swifts are birds that spend much of their lives in the air. They are very fast flyers. Some large birds can fly at speeds up to 160 km/h. The common swift can fly at 31 metres per second. In one year, a common swift can fly 200,000 km.

Swifts have a special way of flying. They can rotate their wings from the base. This keeps the wing stiff and wide. This helps them get power on both the upstroke and downstroke. They can also change the shape of their wings to move better.

Many swifts build nests using saliva, which is spit. They glue these nests to walls or in caves. Some people use these nests to make bird's nest soup. Some swiftlets even use echolocation to find their way in dark caves. This is a way to see using sound. Swifts eat insects like flies, ants, and bees. They catch their food while flying through the air.

Swifts are amazing birds that spend most of their lives flying through the sky. They belong to a family called Apodidae. This name comes from a Greek word meaning "footless." This is because their legs are very small and weak. Even though they look like swallows, they are not close relatives. They are actually part of the order Apodiformes. This means they are closely related to hummingbirds. Swifts are built for life in the air.

These birds have a very special way of moving through the air. They can rotate their wings from the base. This keeps the wing stiff and wide while they fly. This allows them to get power on both the upstroke and the downstroke. The downstroke creates lift and thrust to move them forward. The upstroke also creates lift. It also creates a small amount of drag. Swifts can even change their wing shape. They do this by moving the bones at their wingtips. This helps them turn easily and fly at different speeds.

Scientists have studied swift fossils to learn about their history. These birds first appeared during the Eocene period. Fossils have been found in temperate Europe. These fossils were found between places like Denmark and France. One ancient bird was called Scaniacypselus. It lived during the Early to Middle Eocene. Another bird named Procypseloides lived later. It lived from the Late Eocene into the Early Miocene. These fossils help us see how swifts changed over a very long time.

There are about 100 different species of swifts in the world. They live on every continent except for Antarctica. Some swifts are very small, like the pygmy swiftlet. It weighs only 5.4 grams. Other birds are much larger, like the purple needletail. The common swift is a very fast flyer. It can fly at 31 metres per second. In just one year, it can fly 200,000 km. In its whole life, it might fly two million kilometers.

Swifts use interesting ways to make homes and find food. Many species use their saliva to glue nests to walls. Some swiftlets use this saliva to build nests in dark caves. Humans have used these nests for bird's nest soup for over 400 years. To find food, swifts catch insects while they are flying. They eat things like flies, ants, bees, and even spiders. Some swiftlets use echolocation to navigate. This is a way of using sound to see in the dark.

Swifts belong to the family Apodidae, a group of birds defined by their highly aerial lifestyle. The name Apodidae comes from the Greek word "ápous," which means "footless." This name refers to their very small and weak legs. While they look similar to swallows, they are not closely related to them. Instead, swifts belong to the order Apodiformes. This order also includes hummingbirds. The physical similarities between swifts and swallows are actually a result of convergent evolution. This happens when different species develop similar traits because they share similar lifestyles, such as catching insects while flying.

The flight mechanics of swifts are incredibly specialized for speed and control. They share a unique ability with hummingbirds to rotate their wings from the base. This rotation allows the wing to remain rigid and fully extended during flight. Because of this, they can derive power from both the upstroke and the downstroke. The downstroke produces both lift and thrust to move the bird forward. The upstroke is also productive; it generates lift equal to 60% of the lift from the downstroke. However, the upstroke also creates a negative thrust, or drag, that is 60% of the thrust produced during the downstroke. This arrangement likely helps the birds maintain high levels of maneuverability.

Swifts can also change the actual shape of their wings to fly more efficiently. They do this by altering the angle between the bones of their wingtips and their forelimbs. The wingtip bones of swiftlets are proportionately longer than those found in most other birds. This allows them to adjust the wing area for different speeds. There are approximately 100 species of swifts globally. These are generally organized into two subfamilies: Cypseloidinae and Apodinae. Within these, there are four distinct tribes. These include the Cypseloidini, the swiftlets (Collocaliini), the needletails (Chaeturini), and the typical swifts (Apodini).

The evolutionary history of these birds dates back to the Eocene epoch. During this time, the Apodiformes diversified, and the modern families were already present. Fossil evidence has been found throughout temperate Europe, ranging from Denmark to France. One ancient, swift-like genus is Scaniacypselus, which lived during the Early to Middle Eocene. Another genus, Procypseloides, lived from the Late Eocene through the Early Oligocene and into the Early Miocene. Some scientists also suggest that a prehistoric genus called Primapus, found in the Early Eocene of England, might be a distant ancestor of the group.

In terms of physical scale, swifts vary significantly in size and weight. The pygmy swiftlet is extremely small, weighing only 5.4 grams. On the other end of the spectrum, the purple needletail is much larger and heavier. Some species are remarkably fast in level flight. The white-throated needletail has been reported to reach speeds of up to 160 km/h. Even the common swift is a powerful flyer, cruising at a maximum speed of 31 meters per second. The distances these birds travel are staggering. A common swift can cover at least 200,000 km in a single year. Over the course of its lifetime, a single bird may fly about two million kilometers.

Swifts have unique nesting and survival behaviors. Many species use their saliva as a glue to attach nests to vertical surfaces. The genus Aerodramus relies entirely on this salivary cement. This substance is the primary ingredient in bird's nest soup, a delicacy used in Chinese cooking for over 400 years. These nests are often built in caves and are composed of interwoven strands of saliva containing calcium, iron, potassium, and magnesium.

To navigate dark cave systems, some swiftlets have developed echolocation. The three-toed swiftlet has even been observed using this method to navigate at night outside of its roost.

Ecologically, swifts play a vital role by consuming various insects while in flight. Their diet includes dragonflies, flies, ants, aphids, wasps, bees, and even aerial spiders. While they are widespread, they are not found everywhere. They live on every continent except Antarctica, but they avoid the far north, large deserts, and many oceanic islands. Some species in temperate regions are highly migratory and spend winters in the tropics. To survive short periods of cold, some species can enter a state called torpor, which is similar to hibernation. While many species are stable, some, like the Guam swiftlet, are considered endangered due to various factors.