For millennia, folk in most parts of China have regarded swallows coming to their homes to build nests as a sign of good fortune.
The first encyclopedia of life article was used to describe Jia Yan
1. In the old days, Wang Xie Tang Qianyan flew into the homes of ordinary people
The house swallow is one of the 74 species of birds in the swallow family, usually in black and white, also like the color of the giant panda, often inhabiting the roofs of villages in pairs or in groups.
It feeds on mosquitoes, flies and other pests, according to scientific statistics, a swallow can eat hundreds of thousands of pests in spring and summer, so it is a beneficial bird and friend of human beings.
There are about 10 species of swallows in China, the most common of which are the house swallow, sand swallow, golden-waisted swallow, spotted swallow, hairy-footed swallow, etc., for different families of swallows, their nest shape and nesting site are different.
The figure below shows the corresponding nest shapes of the four common swallows.
The folk often say that the swallow mostly refers to the house swallow and the golden-waisted swallow that nest in the eaves of the house. The physical characteristics of the two of them are very similar, but the nest shape is very different, the following pictures are physical photos of the two, can you tell which species of swallows inhabit your family yard?
Home swallow nest
Golden-loined swallow nest
2. The swallow camp nests to rely on, and the mud is hard to fly
nest:
The parent bird takes mud and dry grass stems from the banks of rivers and lakes, mixes them with saliva to form small mud balls, and gradually piles them up from the base with their mouths to form a solid shell, and then lays fine grass/bird feathers on the inside to form a comfortable inner cushion, the whole process takes 8 to 14 days to complete
The role of nesting on reproduction:
1. It has a good thermal insulation effect, and relevant studies have found that even when the external temperature is 0 °C, the temperature in the nest can still be maintained at 18 ~ 23 °C, which can save 40% of the energy for the incubation of the brood;
2. The "high" and hidden nest can help the family swallow avoid aggression or predators
After 14 to 15 days of incubation in the nest, the chicks emerge from the shell, and after about 20 days of feeding by the parent birds, they begin to emerge from the nest, learning to hunt and fly under the leadership of their parents, in preparation for the next southern wintering
3. Where to go in autumn, spring comes and goes
The house swallow is also a type of summer migratory bird, and every autumn, the swallow will fly south with the young birds born that year
This is the global distribution map of the family swallow, the yellow area is its breeding area, the blue area is the winter area, which shows how difficult the way to migrate south to winter, the migration of the European swallow will be very painful, must cross the Sahara Desert in Africa and can not rest in the middle, and the Chinese swallow, except for a few will stay in Guangdong/Yunnan and other places for winter, most of them will fly out of China and go to South Asia, Southeast Asia and Australia for winter. They will not return to the north until March and May of the following year
According to statistical surveys, in this round-trip migration of thousands of miles, the probability of successful return of the northern swallow to the nest every spring is about 47%, and the two necessary elements that affect the success rate are energy and navigation.
Whenever it comes to the migration season, jiayan can show "migration excitement" by feeling the change of sunshine time, and will instinctively stimulate the "gene" in the body to control overeating, and desperately eat to accumulate fat for the next ocean migration.
According to the results of relevant scholars through the study of bird rings, birds weighing 100 grams will consume about 1 gram of fat for every 54 kilometers
With sufficient energy storage, the ocean migration is only half successful, so how did Jia Yan successfully identify the direction and reach the destination?
This ability of swallows has been continuously studied and explored by many scholars. At the same time, there are many theoretical theories, until the 21st century, the discovery of the magnetin Magr receptor and cry made the famous geomagnetic induction theory more and more accepted by more and more people.
In the principle of geomagnetic induction theory, geomagnetism/biological protein/bird migration/quantum mechanics are linked, if it is too complicated to investigate deeply, by consulting the relevant literature, the subject only understands the surface, if the expression is simpler, then - the swallow can "see" the earth's magnetic field with its eyes
The "seeing" here does not mean that the swallow can really see the earth's magnetic field, in fact, the geomagnetism by affecting the reaction conversion rate of a certain free radical in the swallow's body enables it to perceive the direction of the geomagnetism, and then combines the effect of light-sensitive proteins on the real scene to form a real-time angle on its retina, so what does the swallow really see in its eyes when it starts the migration mode?
For more clarity, we have created the following simulated azimuth map. The perception of gravity by the vestibular system of the house swallow is that it can distinguish between north and south (and at the same time breaks the embarrassment of the reverse flight when the same "modulation model" in the field of vision), in this way, the house swallow constantly perceives the orientation through the angle between the geomagnetic vector and the horizon, so that it can accurately "navigate" to the destination
These are only the embodiment of the role of vision in the migration process of the house swallow, in addition, the smell /touch / strong memory of the house swallow may also play an important role in the migration process, and different scholars are also studying the process. The subject believes that one day in the future, scientists will have a clear understanding of Jia Yan's "divine power" and use it for people
The above is the secret of JiaYan, more life encyclopedia articles welcome to pay attention to the subject's WeChat public account "Today's theme", thank you
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