I have heard others say that there is a bird in this world that has no feet, it can fly all the time, it can fly and fly, and when it is tired of flying, it sleeps in the wind, and this bird can go down to the ground once in a lifetime, and that time is when it dies... —— "The Legend of Ah Fei"
Even if you haven't seen this movie, you must have heard this classic line. The footless bird in the movie refers to the bird of paradise, which is known for its gorgeous feathers, but in fact, the bird of paradise also has feet and does not have outstanding flight ability.
The name of the legless bird comes from a cruel legend: Columbus returned from a voyage and presented a magnificent bird skin to the king, and Westerners found that the bird had no feet and imagined the bird flying non-stop in the sky. But the truth is that Columbus's bird skin was obtained from an indigenous chieftain, who thought that the legs on the bird's skin were not beautiful and cut it off.
Fly in the air, sleep in the wind, and leap 35,000 kilometers a year
Although the legend of the bird of paradise without feet is false, there is a kind of bird that is really called the legless bird.
Swift, 92 species in 19 genera, its Latin literary name "Apus", translated as "footless bird". They spend most of their lives flying, hunting, courting, mating, and even resting in flight, and when it lands, it almost means death.
Swift is not large, similar to the palm of an adult, weighing only 29 to 41 grams, equivalent to an egg, Swift has a streamlined body, the open wings are wide and long, almost three times the size of the body, the shape of the wings is similar to a sickle, and the tail opening is a shallow split. Its light body and special structure make the Swift extremely capable of flying, and more importantly, it can save a lot of energy when gliding.
Swifts can fly at speeds of 110 to 200 km/h, making them one of the fastest birds in the world for long distances. Its flying action is also very beautiful and agile, in the urban area of Beijing, you can often see swifts flying up and down between the city towers, because before and after the rain, swifts are the most active, so it is named Swift.
Swift's beak is very small, it does not look like it is open, but a mouth, the mouth can almost cover the entire face, this mouth is like a net pocket, with the speed of the swift, with the speed of the swift to cover the air of the flying insects "pocket", swift recipes contain mosquitoes, flies, flies (méng) and other pests, swifts alone when feeding chicks, a day to catch more than 7,000 insects, in the entire brooding period can catch at least more than 250,000 insects.
Each pair of swift parents can raise 2 to 3 chicks, and the chicks learn to fly after about 40 days of birth and never return to the nest. By the end of July and the beginning of August, these chicks follow their parents on the migration path to complete the most important trials of their lives. The migration began in Beijing and spanned Mongolia, the ancient Silk Road, the Arabian Peninsula, and eventually reached South Africa, spanning more than twenty countries. Swift will return home after 3 months of rest in South Africa. Swifts fly 830 kilometers a day, 35,000 kilometers round trip, almost once around the equator.
Swifts on the migration route, are the choice of those bred a large number of mosquitoes in the area, such as the Mongolian steppe, swifts while flying while hunting flying insects, when passing through the water source, swifts will also be like dragonflies dotting the water, quickly skimming the water surface, completing drinking water, leaving only ripples on the surface of the water.
When the swift is tired, it sleeps in the wind. Swifts have a unique way of sleeping, with swifts flying high enough before closing their tails and spreading their wings to start gliding. At this time, their speed will be reduced to 30 kilometers per hour, and the wings will be regularly instigated to maintain this speed, and then the left and right brains will rotate to sleep, which is called "hemi-brain slow-wave sleep". According to research, Swifts can fly in the air for ten months without stopping, eating, drinking, and resting in the air.
"Footless bird" Swift is not without feet, but their foot structure is special, ordinary bird claws are "front three back one", can grasp the branches very well, but swift's claws are four toes are in front, and the fingertips are curved, Swift can be firmly hung on the surface of the rock wall by this structure.
The swift's flight must also glide down from a height, and once it falls on the ground, it is difficult to take off without the help of external forces. You can only crawl clumsily and the ground, either eaten by predators or you will be starved to death. Therefore, when swifts land on the ground, they often represent their death.
An indissoluble relationship with Beijing
Swifts have a soft spot for Beijing, and when summer comes, swifts migrate back from South Africa. At this point, they will begin to prepare for the next generation. During the breeding season, the male swifts will fly high into the air, then glide down, maintain a smooth flight, and then stick with the female petrels to complete the mating in the air in just a few seconds.
But birds are all oviparous after all, and swifts still have to build nests for the next generation. Swifts collect materials during low-altitude flights, or grab waste paper, feathers, hay and other materials blown up by the wind, and use saliva to bond to build nests.
Original swifts would nest between crevices in cliff faces, but in long-term evolution, Swifts developed the habit of nesting in the ceilings or crevices of tall ancient buildings, and their nests were generally 4 to 45 meters above the ground, and only at this height could Swifts take off and survive normally.
Swifts have the habit of breeding in groups, so groups of swifts will nest on a building, and after building a nest, every year after the swift will "go home", so between these buildings, you can often see the incessant orthodals, and the swifts are also called "lou swallows".
Beijing has a long history of architecture, once the imperial capital of the 5 dynasties, the Forbidden City, the Temple of Heaven, the Taimiao Temple, the Forbidden City, the Bell and Drum Tower and other ancient buildings, between the arches of these buildings, the formation of artificial caves. For Swift, these small and hidden spaces are not only comfortable, able to block the invasion of rain and wind, but also to avoid predators, so Beijing has become an important habitat for Swift.
Swift has been hovering over Beijing for hundreds of years, witnessing the rise and fall of dynasties and the changing of the world, but Swift has never really left. Swifts have become part of Beijing's culture, and the image of the mascot "Nini" of the 2008 Olympic Games comes from Swift.
Nowadays, beijing's loutai temples and other ancient buildings have been demolished for various reasons, high-rise buildings have risen from the ground, in order to protect ancient buildings, such as the Forbidden City and other places have also hung anti-bird nets, the habitat of Beijing Swift has decreased sharply. According to the 2014 China Bird Watching Association, there are fewer than 3,000 swifts in Beijing, and many people remember that under the sunset, the scene of swifts in the sky has disappeared.
But experts have also been running for the protection of Swift, in 2018 Zhengyang Gate launched the project of "ancient building protection and urban ecology", and the final study showed that Swift feces do not harm wooden ancient buildings, which undoubtedly has positive significance for the protection of Swift. The China Bird Watching Society and the China Garden Museum also tried to hang artificial nest boxes to attract swifts to nest. Swifts have also been found shuttling between the holes of antique and some modern buildings in search of nesting sites.
Now, it's time for the Beijing Swift to migrate again, and I wish them a smooth journey and see you again next spring.
Resources
Beijing Swift Zhang Shiqiang
"Beijing Swift - Flying Over Thousands of Miles to Accompany You" Zhang Zhengwang
"Beijing Swift Doesn't Take the Usual Path" Yang Zixuan
Beijing Swift and Beijing Ancient Architecture, Gao Wu