The Amazing Abilities of Hummingbirds: How Do They Stay in the Air? What's the Principle Behind It?

Have you ever marveled at the flying skills of hummingbirds? They can stay still in the air, move up and down like a helicopter, and even fly backwards. They are the only birds that can do this, and they are also one of the smallest birds in the world. They can fly at speeds of up to 54 kilometers per hour, and their wings can beat up to 80 times per second. Their flying abilities are amazing and have scientists intrigued. So, how do hummingbirds hover in the air?

1. Hummingbird Wing Structure

To understand how hummingbirds fly, we first need to look at the structure of their wings. Hummingbirds' wings are very flexible and can rotate in three directions: forward and backward, up and down, and left and right. This allows them to control the angle and direction of their wings, thereby generating different airflows and lift. Lift refers to the upward force of air on an object, which determines whether an object can fly.

When hummingbirds fly forward, they flap their wings backward so that the leading edge of the wing is at an acute angle to the horizontal plane. This creates a low-pressure area above the wing and a high-pressure area below the wing. Due to the pressure difference, the wing is subjected to an upward lift. This lift is the basic principle of flight for most birds.

However, when hummingbirds want to hover in the air, they flap their wings forward so that the leading edge of the wing is at an obtuse angle to the horizontal plane. This creates a low-pressure area below the wing and a high-pressure area above the wing. Due to the pressure difference, the wing is subjected to a downward lift force. This lift force counteracts the gravity force, allowing the hummingbird to maintain balance.

2. How hummingbirds move their wings

In addition to changing the angle of their wings, hummingbirds also change the way they move their wings. Generally, birds speed up when flapping their wings downward and slow down when flapping them upward. This is done to save energy, because when flapping downward you have to overcome gravity, while when flapping upward you can use gravity. However, this also means that lift is only generated when flapping downward.

Hummingbirds, on the other hand, accelerate their wings both downward and upward when they fly, changing the angle of their wings in each direction. This is done to increase lift, since lift is generated when flapping both downward and upward. Although this method consumes more energy, it also allows hummingbirds to adjust their flight direction and speed more flexibly, and they can even perform some amazing maneuvers in the air, such as flying backwards, diving, and hovering. The wing movement of a hummingbird is similar to a person paddling in the water, and can generate thrust in any direction.

3. Hummingbird flight efficiency

Although the flight of hummingbirds is admirable, it comes at a cost. Because their wings flap so frequently, they use a lot of energy. A hummingbird needs to consume twice its body weight in nectar every day to maintain the calories needed for flight. If they stop eating, they may die within a few hours. Therefore, hummingbirds must constantly seek out flowers, suck up nectar, and use their sensitive tongues and beaks to filter out the excess water.

To improve their flight efficiency, hummingbirds also use external factors, such as wind, air pressure, and temperature. For example:

When there is a tailwind, hummingbirds will reduce the frequency and amplitude of their wing flapping to save energy. When there is a headwind, hummingbirds will increase the frequency and amplitude of their wing flapping to overcome resistance.

When the air pressure is low, the air density is low, the lift is weak, and the hummingbird will increase the frequency and amplitude of wing flapping to maintain balance. When the air pressure is high, the air density is high, the lift is strong, and the hummingbird will reduce the frequency and amplitude of wing flapping to avoid excessive rise.

When the temperature is low, the air density is high and the lift is strong, so hummingbirds will reduce the frequency and amplitude of their wing flaps and shrink their bodies to maintain body temperature. When the temperature is high, the air density is low and the lift is weak, so hummingbirds will increase the frequency and amplitude of their wing flaps and expand their bodies to dissipate heat.

4. What hummingbirds can teach us about hovering in the sky

Hummingbirds can hover in the air because of their unique wing structure and movement, as well as efficient energy utilization strategies. These characteristics enable them to adapt to various environments and conditions and complete tasks that other birds cannot do. For example, they can stay in the air on flowers, absorb nectar, and spread pollen. They can also chase, attack or escape enemies or competitors in the air. They can also court, mate or raise offspring in the air.

The flying ability of hummingbirds is not only beneficial to them, but also to humans. By observing and studying the flying principles and skills of hummingbirds, humans can design and manufacture more advanced aircraft or robots.

For example, NASA has developed a hummingbird-like micro-aircraft that can hover, turn, and fly in the air to explore the environment and terrain of Mars or other planets. Similar projects include Japan's hummingbird robot and China's hummingbird drone. These aircraft or robots can complete tasks that humans cannot or are inconvenient to complete in some complex or dangerous situations, such as reconnaissance, rescue, monitoring, or transmission.