What is the smallest bird in the world?

In the blooming flowers, a bird danced and stopped abruptly in front of a red flower. It didn't land on the flower branch, but circled in the air like a helicopter, ate the nectar carefully with its slender beak, and then left quietly. This is a hummingbird, a bird unique to the Western Hemisphere.

There are about 300 species of hummingbirds in the world, most of which live in the tropical rain forests of South America. Hummingbirds have three flying skills: flying backwards, rising and falling vertically, and staying in the air.

Hummingbird is the smallest bird in the world, about the size of a bee, with a body length of only 5 cm and a weight of only about 2 g, mainly distributed in forest areas of South America and Central America. Because it can make a buzzing sound when flying to collect honey, it is called hummingbird.

There are many kinds of hummingbirds, about 300 species, and dozens of colors of feathers, such as black, green and yellow, which are very bright, so they are called "God Birds", "Comets", "Forest Goddess" and "Corolla". Hummingbirds are petite, gorgeous in feathers and have extraordinary flying skills. Its wings are very flexible, can vibrate 50 ~ 70 times per second, and fly very fast, with a speed of 50 kilometers per hour and a height of four or five kilometers. People often only hear its voice and can't see its figure clearly. Hummingbirds go out for food in the season of blooming flowers and lush vegetation, and live on nectar and small insects.

Hummingbirds nest on branches. These nests are unique in shape and fine in workmanship. They are made of silk and look like delicate wine glasses hanging from branches. The female hummingbird lays one or two eggs at a time, only the size of a bean, each weighing only 0.5 grams, and about 200 hummingbird eggs are as big as an ordinary egg. The incubation period of bird eggs is 14 ~ 19 days. Hummingbirds can fly out of their nests for food and start an independent wild life about 20 days after birth.

How do hummingbirds fly and hover in the air? Seventy years ago, ornithologists took a large number of films of hummingbirds flying in the wild with high-speed cameras, and then showed them at normal speed, which slowed down the flight of hummingbirds. As can be seen from these films, when hummingbirds fly, their wings flap vertically up and down on both sides of their bodies; When hovering in the air, the hummingbird's wings flap 54 times per second; Fan 75 times per second when ascending, descending or advancing vertically. Hummingbirds fly and hover by flapping their wings quickly. According to these films, people always think that hummingbirds fly in the form of insects when circling.

However, a new study by scientists from Oregon State University shows that hummingbirds have the characteristics of both insects and ordinary birds, which has been misunderstood by human beings for nearly 70 years. Hummingbirds fly between insects and ordinary birds.

Scientists at Oregon State University reported that they studied the flying patterns of hummingbirds by observing the changes of whirlpools around them when they were flying. Scientists first trained hummingbirds to hover in a fixed position while eating from a syringe filled with sugar solution. Then they added a "mist" formed by tiny olive oil particles into the space where the hummingbird flew, irradiated the hummingbird from all angles with laser rays, and took two photos every 1/4 seconds to capture the distribution pattern of oil particles. Judging from the distribution of oil particles, hummingbirds will lift their bodies and spread their wings to both sides while flapping their wings up and down. Scientists have found that in order to get lift, hummingbirds fold their wings and point them in the right direction every time they flap their wings. The posture of its wings when flying is actually similar to that of a swimmer's arm when stepping on water, but the frequency is much faster.

Scientists point out that all the lift needed by other birds when flying comes from the fan under their wings; Half of the lift of insect flight comes from the fan under the wing, and the other half comes from the fan on the wing; However, 75% of the lift of hummingbirds comes from the fan under the wings, and 25% comes from the fan on the wings. From the aerodynamic point of view, the flight mode of hummingbirds is between insects and ordinary birds.

Scientists said that this discovery will help deepen people's understanding of the evolution of bird hovering technology. Hummingbirds are different from insects, but they seem to have learned to make insects fly with the wings of birds. Birds' wings can stretch, bend and arch, which rigid insect wings cannot do.