1 week, 6 days ago


In Wong Kar Wai's film, a kind of bird with no feet is mentioned to describe the protagonist's wandering life. 

Looking horizontally and vertically, this kind of bird is like a literary symbol. And its prototype is indeed a fictitious product of "Paradise Bird". In order to preserve the specimens, the merchants would cut off the legs of the birds of paradise, which gave birth to a legend of "divine birds". 
The bird of paradise in 
 ornithology (1599) is the prototype of the bird of paradise. However, the bird of paradise has not only feet, but also ordinary flight ability. Source: Wikipedia 
 but in real life, only the magical swift is worthy of the title of "footless bird". 

Swifts spend most of their lives flying, landing a handful of times. Apart from sleeping in the wind, eating and drinking Lassa, and even mating are done in the air. 

 the record of not landing for 10 consecutive months has been beyond the reach of all birds. But that may not be the limit. 

 common swift (Apus apus), source: Marcel van Kammen / Minden pictures 

. However, both Apodidae and Apus come from the Greek language á pous, meaning 

Of course, swifts don't really have no feet, but their feet have seriously deteriorated. Unlike other birds, swifts have four forward toes (one of which rotates freely back and forth). 

 the comparison of different types of toes of several birds, e is the foot of swift, so they can only climb on the rough vertical plane such as trunk, cliff, wall, etc., but it is very difficult to stand on the ground, not to walk and jump. 
COM / v2-8c37c1e843e90c8fb62bd2b77a18a4ub. JPG "ALT =" " Width = "512" >. Other birds can pedal with their feet to get a thrust to take off quickly, but swift can only use long wings to flutter a few times, taking off is very difficult and very slow. 

Therefore, the landing swift is very dangerous, almost equivalent to giving other animals lunch. 

In addition, they want to take off successfully on the premise that the ground is flat enough. If they fall into the grass, they may be in danger. And these characteristics also make them reluctant to land on the ground, "footless bird" hence the name. 

 ordinary swift, source: Joelle a Godfrey 
 of course, as a master flier in birds, swift basically does not need to land, so it's over. 

The body of swift is small, but its wings are big and slender, which makes it easy for them to fly. It looks like the familiar domestic swallow (Hirundo rustica). 

. And these similar characteristics are more the result of convergent evolution, which are conducive to flight. 

Now, we have classified domestic swallows into Passeriformes. The swifts and hummingbirds are the real family, both of which belong to the order of delphiformes, although one is like a helicopter and the other is like a glider. 


The flying speed of swift can reach 110km / h, which is beyond the reach of many predators, so there are not many natural enemies of swift. But at the same time, swift can keep flying. 

. The breeding season of common swifts is from late April to mid September every year. But apart from the two months it takes to breed offspring, swift flies 99% of the time. 

As early as 50 years ago, ornithologists have discovered their incredible flight ability. But suffer from only indirect evidence, such as no common swift found in the wintering area of swift, people always have opinions on how long it can fly. 

 it wasn't until a follow-up study in 2016 that we were finally overwhelmed by Swift's amazing ability. 

 source: drakuliren/ Shutterstock 
 at that time, researchers equipped 13 independent ordinary swifts with micro recorders and accelerometers to track and observe their annual flight routes and activities. It was found that some Swallows had not landed for 10 months. 

The life span of swift is very long, the highest record can reach 21 years. Calculated, the distance that swifts leap in their lifetime is enough to travel back and forth between the earth and the moon several times. 

However, 10 months is nothing. After the follow-up study, ornithologists also boldly speculated that swifts may have set a longer flight record than 10 months ago. 

As mentioned earlier, in addition to breeding offspring, swift is eager to never land. But in fact, 
 their flight time records are also related to the length of breeding period 
. Before the ordinary swifts, the high mountain swifts (Tachymarptis Melba) set a flight record of more than six months in 2013. The main reason why they don't last long is that the annual breeding period is too long. 
Yes. Until two years later, when they are sexually mature, they will stay to build nests and forage for young birds to complete the task of succession. 

Therefore, in the growth period of these two years, it is likely that swifts will not land without accidents. Only so far, there is no actual track record to prove this. 

 source: swift conservation Org 
 so in addition to taking the baby, they eat, drink, pull, mate and other behaviors, all can be completed in the air, that is to say, living in the sky is not too much. 



Indeed, in the case of food shortage and severe cold, swift can enter the sleep mode of low energy consumption, and the whole body temperature drops suddenly. This state can last from a few days to 10 days, but it can only be seen in young swift. This is their survival strategy. When the cold wave comes or their parents can't take care of them in time, these cubs still have a chance to survive. 

 the common young swift that has not yet learned to fly. Photo source: Wikipedia 
 however, you can't live on your own. They always have to grow up and fly to the sky alone. 

Since learning to fly, swifts have to find their own food. Swift is a kind of insectivorous bird. By opening their mouths in the air, they can catch all kinds of flying insects. 

 small body, large mouth 

 and this predatory behavior also makes swift a weather forecaster in the animal kingdom. Every time the swallows fly low and sing, they say it may rain tomorrow. Because of the low air pressure before the rain, the flying insects could not fly to the high place, and they all lived on the water surface and the grass on the ground. The swift had to fly low with the insects. 

Sometimes when they skim over the water, swifts can drink a few mouthfuls. In fact, even the materials used to build nests are all picked up from the sky. 


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