Birds without feet, the original existence

The beginning of autumn has passed, and the weather turns slightly. Just as we lamented the changes in the weather, a bird set foot silently on its own journey, and the empty nest indicates that this cute elf has been marching to Africa.

This "love" bird is Beijing Swift. From April to July each year, Swift from Beijing will come to Beijing not far away. In about 90 days, it will produce, incubate, and cultivate, and go to Africa when the weather turns cold. Essence

Swift flying in the air (picture source: globaltimes.cn)

1. The "pilot" who almost does not land

Speaking of Beijing Swift, everyone may not be familiar with, but when it comes to Nini, one of the "Fuwa" of the 2008 Beijing Olympics, everyone will definitely not be unfamiliar. In fact, Nini's prototype is Beijing Swift.

The APUS APUS Pekinensis is actually a subspecies of APUS APUS. In 1870, British maternalist Robert Swenhou discovered that Beijing's Swift was different from the European Swift in the form.

Beijing Swift (Picture Source: pbase.com)

The Beijing urban area is the main distribution and breeding place of Beijing Swift, while the distant counties are relatively small. Because Swift belongs to poultry climbing, it requires mountain rock seams or caves to build nests. Since the movement of Beijing, Beijing has built a large number of buildings. These buildings have formed artificial caves one by one. Safe and comfortable, for a long time, Swift has slowly used to breeding nests in Beijing.

Whether it is ordinary swallows in Europe or Beijing Swift, in July each year, they leave the habitat and migrate to the central and western regions in central Africa. Although they traveled to Africa long distances, it was surprising that their feet may never set foot in Africa land.

They are foraging in the air, mating in the air, and obtaining nesting materials in the air. They may land on branches or houses, but they will not really land on the ground because their legs and feet are short and their wings are long. Once they fall in flat ground, they fall in flat ground. , It is impossible to take off again with the help of leg strength. If it is not rescued, it will almost indicate the fate of death. Therefore, Swift is also called "bird without foot". Its name and species "APUS" originated from the Greek "APOUS", which means "footless". I have to sigh, the ability to classify the scholars is really amazing.

The little Jiojio of Swift (Picture Source: MERSEYSIDERG.UK)

In order to figure out how long the Swift will stay in the air, in 2013, several scientists from the University of Rom, Sweden installed light data record devices for 19 Swift, and re -captured them one or two years later. The researchers judged that they were flying at the time through data such as the acceleration and physical posture recorded by the device.

Data show that some rainy swallows have almost never stopped activities during the long migration process. For example, scientists found that from September 2013 to April 2014, a Swift only rested in February for four nights in February; in the second year, this rainfall never had a whole night, specifically specific, specifically specific In terms of, it only rests for two hours. According to the calculation of scientists, during the process of migration, Swift spent only 0.64%of the whole journey.

Swift (picture source: newscientist.com)

Such a long flight time means that Swift must be able to sleep during flight. Although there is no small sensor that can be used to monitor the changes in brain waves when the Swift is flying, research on warships shows that birds can indeed sleep on the way. Perhaps, Swift is like a warship bird. He sleeps a few seconds each time and revives the spirit. Maybe only this can make them cross thousands of mountains and rivers, and you can travel tens of thousands of kilometers for a long time!

Second, this is a trip of more than 30,000 kilometers

In fact, although people have been curious about the flying ability and migration route of Swift for a long time, because the Swift is too small and too light, only 30-40 grams weighs, and a slightly heavier device will affect the normal flight of Swift.

Wearing ordinary swallows (picture source: Commonswift.org)

Therefore, earlier, people tried to understand the flying traces of Swift through the circular (special, coded metal foot ring). However, everyone knows that Swift is flying fast and flying far away. The biggest role of Huanzhi may be used to estimate the loyalty of Swift for breeding places. If you want to know where they fly and where they go through, you have to find other ways.

The Guangmin positioning instrument is a new method found by scientists in recent years. The net weight of the positioning instrument is only 0.65 grams. The impact on Swift flight is relatively small, and the Guangmin elements on the positioning instrument will record the high angle of the solar and sunrise and sunset. After recycling the positioning instrument, scientists can calculate the relatively accurate migration path of Swift through a set of data.

Guangmin Positioner (Picture Source: References)

Let's take a look at the rainfall in the installation of the Guangmin positioning instrument. Is it like a small schoolbag on his back? When the Swift returns to the original habitat in the next spring to reproduce, scientists can recycle these positioning instruments, and then make sure where they go, where to stop! In 2012, a paper published in the journal "Public Science Library" studied the migration trajectory of ordinary Swift in Europe. These aerial elves will pass through Europe to the south, then fly to the southwest Sahara desert to the Congo Basin.

The migration trajectory of ordinary Swift in Europe (picture source: reference)

Compared with these European relatives, the Beijing Swift is farther in the distance from the wintering place to the winter, and the fact is exactly the case.

In May 2014, the Chinese Bird Watching Association wore a positioning instrument to 31 Swift in Beijing. In May of the last year, they recovered 13 rainfall wearing a positioning instrument. Although the number was small, it still provided us with a lot of effective information about Beijing Swift migration.

This work continued until 2018, and scientists recovered a total of 25 optical positioning instruments, of which 5 of them had two years of tracking data. Based on the data provided by these positioning instruments, scientists have drawn the migration routes of Beijing Swift to Africa to spend winter, and then return from Africa to Beijing. The relevant articles were published in the journal "Sports Ecology" in July this year.

The track of the left is the trajectory of the wintering of Africa, and the trajectory picture of returning to Beijing on the right is Source: References

It is amazing that this migration journey has surpassed the distance of almost 30,000 kilometers. Specifically, Beijing Swift has left Beijing since July. After more than 3 months, it has reached the wintering place of the South African plateau. This half has almost 15,000 kilometers, which means that these rain swallows fly more than 130 kilometers a day. In the spring of the next year, Swift returned from Africa to see you. This distance is not short, but the Swifts rushed back to reproduce. The flight speed was fast, and the return journey could be completed in almost two months.

Therefore, there was a saying that a Swift in Beijing was before the natural old death (14 years of life), and the distance of the flight can already exceed the average distance between the earth and the moon (384403.9 kilometers).

Swift is really an amazing creature!

3. Swift in Beijing, more protection is needed

However, everyone may not know that this life belongs to the sky, and has been crossing thousands of mountains and waters, and even more than ten years ago, even on the verge of disappearing.

According to the "China Green Times" report, in the early 20th century, the number of swallows in Beijing had reached its heyday, about 50,000, but with the acceleration of Beijing's urbanization process, the Swift had only about 3,000 in Beijing at the beginning of this century. , And continued to decrease in more than 10 years in the next year. In 2014, the data statistics from the Beijing Bird Watch Association showed that there were only 2,700 Swift in Beijing.

Beijing Swift (picture source: osme.org) where the accompanying person lives

Beijing Swift is accustomed to built a nest on the artificial buildings to build offspring on the artificial building, but in recent decades, there are fewer and fewer buildings such as Beijing City, temples, and ancient towers. Essence Not only that, after the 1980s, the protection of each unit for ancient buildings also affected the survival of Swift. People believe that the feces of Swift may corrode the wood and paint surface. Giving Swift is not enough, the home is in front of him and cannot return, and the survival status is at stake.

The dilemma of Swift made bird lovers and experts very anxious, thinking about it, and decided to provide new nest buildings for the Swifts. In 2008, the Swallow Tower was erected in the Beijing Olympic Forest Park, but it was embarrassing that the Swallow Tower was not a swallow, but a sparrow full of sparrows.

In 2018, in order to understand whether the Swift will adversely affect the ancient buildings, a subject entitled "Ancient Construction Protection and Urban Ecological Research -Taking Swift in Zhengyangmen as an example" was officially launched. Data, the pH of the stool and the nest acupoint is neutral, and the fungus, bacteria, and the nest acupoints in the nest are not found in the flora that constitutes degradation or corrosion in the microorganisms in the microorganism. In other words, Swift will not have a substantial impact on ancient buildings. In this regard, experts believe that creating a new nest is better to protect the ancient buildings that can be built in the nest.

Just when everyone was unable to do it, experts and volunteers found that Beijing Swift was also constantly suitable for changes in Beijing. Their nesting land spread out from ancient buildings. Under the bridge, the eaves of antique buildings, and the caves of old -fashioned buildings, and the caves of the old and damaged in modern building began to appear.

Recent data shows that the population scale of Swift in Beijing has increased to more than 10,000. We hope that in the future, this kind of birds accompanied by Beijing can still fly freely in the sky in Beijing!

Produced: Popular Science China

Author: EVEE

Producer: China Science Popularization Expo

references:

Hedenstr am, A., Norevik, G., Warfving, K., Andersson, A., Bäckman, J., & åKESSON, S. (2016). Annual 10-Month Aerial Life Phase in the Common Swift Apus Apus. , 26 (22), 3066-3070.morganti, m., rubolini, d., åkesson, S., Bermejo, A., de la Puente, J., Lardelli, R., ... & ambrosini, R. R. R. R. R. R. R. R. R. R. (2018). , J. W., & Hedenström, A. (2012). Migration routes and strategies in a highly aerial migrant, the common swift Apus apus, revealed by light-level geolocators. PloS one, 7(7), e41195.

Zhao, y., zhao, x., wu, l., mu, t., yu, f., kearsley, ... & liu, y. (2022). A 30,000-km Journey by APUS APUS Pekinensis Tracks Arid Lands BetWeen Northern CHINA and SOUTH-WERICA. Movement ecology, 10 (1), 1-12...

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