Text|Science Wormhole
There is a kind of bird in the world that spends almost all of its life in the air. When they are tired, they will fly while sleeping. Landing is equivalent to death for them. This kind of bird is Swift .
Although Swift has a "swallow" in its name, it is not in the same family as the common house swallow . The latter belongs to the passerine swallow family; Swift is another Family, There are 84 species of birds in the Swift family, including common Swift, Chimney Swift and so on.
Swifts are famous migratory birds, some are resident birds in tropical regions. Most of the Swift body feathers are darker in color, black or brown, some have bright white/light patterns, and a small number of them are colorful and shiny in a short time.
The biggest feature and advantage of the Swift is flying. It not only flies fast and high, but also flies for a long time. It is the long-distance flight champion in the bird world.
Swift: flying fast and lasting
It is understood that the Swift can fly at a speed of 110-200 kilometers per hour, and some can even reach more than 300 kilometers. It is one of the fastest flying birds in the world.
Even, their names are closely related to "speed".The common name of the Swift family is "swift", as an adjective it means "agile" ; the scientific name of Swift is "Apus", in Greek strong is strong strong "Birds without feet" ;
The previous name of Swiftlet was "Machrochires", which means Bird with developed wings _strong4 span _strong4 . The Swift body is 10-30 cm long and has large wings. Take the common Swift as an example, the average body length is 16 cm, but the wingspan is 42-48 cm, which is three times the body length.
Just like the scientific name "Apus" of the genus Swift, they seem to stay in the air all their lives, fast, and good endurance. Some scientists have studied the flying behavior of Swifts. They have attached special devices to 13 Swifts to track their flight. The results of
were surprising. Some Swifts flew for 10 months without landing .
In 2014, the Chinese Bird Watching Organization gave 31 Beijing Swift a photosensitive locator to study their migration and provide them with better protection.
The results are also surprising. One of the Swifts began to migrate south in July and returned in April of the following year. Within a year, the flight distance of alone during migration exceeded 26,000 kilometers .
After calculation, the Swift weighing only 40 to 50 grams can fly more than 30,000 kilometers in a year. So, how do they do it?
Why is it so powerful?
The huge sickle-shaped wings and streamlined figure is the flying weapon of Swift, which guarantees greater lift and flying speed. The reason why Swifts can fly in the air for a long time is also related to their physiological characteristics.
Swift's Eating and drinking are all done in the air . They mainly feed on insects and spiders, can prey on many agricultural and forestry pests, and are mainly caught in the air, and can catch 7000 insects a day.
They won’t stop drinking water,Instead, drinking water while passing by the water is a real "flight on the water".
The problem is here, even if the physiological needs are solved in the air, what should I do if I am tired and sleepy? Swift said: Solve it directly in the air.
Swift can use only half of the brain to sleep while the other side of the brain stays awake. This "half asleep and half awake" sleep style is called "single hemispheric slow wave sleep" . Of course, this is not the patent of Swift, some mammals can also do it.
In summary, Swift is like a martial arts master who is known for his light work, but everything has two sides, and they also have weaknesses.
Landing is equivalent to death?
Due to living in the air for a long time, Swift’s legs and feet are severely degraded and become soft and weak. This also causes them to face huge risks once they land.
After landing, other birds can fly to the sky again with the help of jumping; but the Swift is not good, the weak short legs cannot jump, and there is no room to flap the big wings, so it is very Difficult to take off from the ground.
The inability to fly is one aspect, and it also increases the risk of being killed by natural enemies. Swift cannot run or jump on the ground,Can only crawl , if it is discovered by natural enemies at this time, you can only consider yourself unlucky.
Swifts rarely stop in their lives, so they are also called "footless bird" . When they stop, it is often to breed and brood.
How to reproduce offspring?
Since the risk of landing is so great, how does Swift reproduce? It turns out that they have a unique mating technique-aerial mating.
Like most birds, Swift’s digestion, urinary, and reproductive systems are common channels _strong1_strong1_strong1_strong . When mating, the flight speed of male and female birds will remain the same, and the mating time is very short.
However, their offspring are still very traditional. They do not fly as soon as they are born, but like other birds, they need to go through the incubation stage, so Swifts need to build nests and brood their chicks.
Swift’s feet are very special,Other birds have three toes in the front and one toe behind, which can hold the branches firmly; but the four toes of Swift's are all facing forward , which means they cannot be on the branch Maintain good stability.
Therefore, whether it is nesting or staying, Swift chooses steep locations, such as cliffs, chimneys, broken logs, etc., and hangs its toes up when landing.
They use saliva to glue twigs, buds, feathers, and moss to build nests, and some use saliva to make nests on the top of the cave. The latter kind of bird's nest is a kind of bird's nest, but it takes a big risk to collect it.
After the nest is built, it hatches. After the chicks break their shells, their parents take turns to feed. In the first few days, the parent birds were fed "food boluses", which are insect chews stored in their throats, sometimes as many as 1,000 insects.
If the weather is good, the chicks can leave the nest in only 5 weeks; if the environment is bad, it will take 8 weeks. The chicks of the common Swift seldom return to the breeding ground after leaving the nest, and do not reproduce until the third and fourth years.
Nowadays, Swifts face more threats, including foraging difficulties caused by shrinking habitats, over-collection of bird’s nests by humans, and widespread use of pesticides to reduce insects and so on.
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