Swallow is a common bird in our country. There are two main types of swallows in our country. One is the barn swallow that we often call . The barn swallow is the most familiar bird to us and the closest to us. The barn swallow is usually found on the eaves. They build nests under the ground and fly to tropical areas such as Hainan in my country or Southeast Asia to spend the winter.
In addition to barn swallows, there is another kind of swallow that is also relatively common, that is, swifts . Swifts fly fast and have loud calls. People can often see them flying quickly in the sky, but they are rarely seen landing in the sky. On the ground, this is because the toes of swifts are hook-shaped and are not suitable for taking off on flat ground. They usually need to jump down from a high place before taking off. Therefore, swifts are also called "footless birds".
In our country, the swifts people usually see are Beijing swift , which is the Beijing subspecies of common swift. It is the only wild migratory bird in the world named after "Beijing". Beijing swifts usually build their nests on cliffs or tall buildings and do not often come close to humans like barn swallows, so they are not familiar to people. Today we will learn about some of the characteristics of Beijing Swift.
Regarding the basic living habits of Beijing Swifts, it has been recorded in many documents. In March and April every year, Beijing Swifts will fly back to Beijing to nest, and in July and August, they will embark on a wintering route to southern Africa. The entire round trip The journey is more than 30,000 kilometers long.
This remote and mysterious migration route has always been a mystery in the minds of many people. How are they located, where do they go, and whether they have a suitable foothold. These mysteries affect every bird lover. Heart. Fortunately, a recent research team composed of Chinese and foreign experts spent four years unraveling these mysteries.
Between 2014 and 2018, a scientific research team composed of experts from Sun Yat-sen University , Beijing Normal University , Lund University in Sweden, the British "Operation Swift" team and the Royal Academy of Natural Sciences of Belgium, It took four years to study the migration behavior of Beijing swifts.
researchers read the flight data of Beijing swifts by wearing miniature photosensitive locators. This locator is very light and will not have much impact on the swifts' long-distance flights. Over more than four years, scientific researchers have installed positioning devices on 66 Beijing swifts, and 25 of them have successfully returned data. These data have become the key to revealing the migration behavior of Beijing swifts.
Data show that Beijing swifts have chosen an extremely remote and difficult migration route.
The route back to the breeding ground: Starting in mid-February every year, Beijing swifts that overwinter in southern Africa begin to move north. This behavior almost starts in the form of large groups, and in a short period of time, it starts from southern Africa. Disappeared without a trace. As the climate in the north gradually becomes warmer and food such as flying insects becomes more abundant, Beijing swifts will stay near the Congo Basin for more than a month, waiting for the climate to warm further.
In mid-March, Beijing swifts migrated again. They quickly turned northeast and left Africa in early April. They continued nonstop, traveling day and night, hunting and resting in the air, until they returned to Beijing in late April. One-way time It lasted 64 days and covered a distance of 13,572 kilometers.
The breeding grounds of Beijing Swifts are mainly concentrated in northern my country, and some will breed in West Asia. At the end of the route of returning to the breeding grounds, the large groups of Beijing Swifts will gradually disperse and disperse to their respective breeding grounds. Like the barn swallow, the Beijing swift has a strong memory and is a migratory bird that loves home. It usually returns to its birthplace to breed.
Route to overwinter in Africa: As the breeding season ends, in mid-July, Beijing Swifts begin to leave their breeding grounds and fly northwest, flying over Mongolia and Xinjiang, my country, and entering Central Asia from the Jungar Basin . Then it flew all the way south, flying over the Red Sea in mid-August and arriving in northern Africa in early September. After resting in the Congo Basin for about 40 days, it set off south again and arrived at the wintering site in November, which is about 1,000 meters above sea level in southern Africa. South African plateau , the entire overwintering behavior lasts for about 100 days and ends.
The comprehensive round-trip route shows that: Beijing Swifts do not migrate all the way, but will choose several places to stop briefly. The main stopping places are the Congo Basin, the southwest coast of the Red Sea and the southern coast of the Caspian Sea. In addition, the speed of returning to the breeding grounds is obviously much faster than the speed of returning to the wintering grounds.
During the Beijing Swift's return route, it will only stop once or twice, lasting about 36 days, and it takes 64 days to return to the breeding ground. When heading to the wintering ground, it is obviously much slower. There will be 2 to 6 stops, about 71 days, and the entire journey takes about 4 months.
There are two main reasons why Beijing swifts adopt a more direct migration route and faster migration speed when returning in spring. First, because of different needs. The breeding period is the most important time for swifts, and it is also the most important time for food. It’s an abundant season, so the need to return is more urgent. During the winter, on the one hand, they have to take care of the newly grown baby swifts. On the other hand, the lifestyle of Beijing swifts in the overwintering area is similar to wandering, and they concentrate on cliffs and other places, so there is no need to urgently arrive.
The migration journey is not only long, but also full of dangers. Predators are waiting for opportunities, and even humans are not far behind.
Compared with other swifts, the Beijing swift is a more drought-tolerant bird. The rainfall in its breeding areas is generally low, and it has to cross many deserts such as the Sahara Desert during migration. The direct driving force for the migration of Beijing swifts is not the arrival of the cold season, but the need for food. After the weather turns cold, insects decrease significantly, and Beijing swifts are forced to migrate to obtain sufficient food.
The entire migration route of Beijing swifts is very far, and many old swifts have died on the way. This is why it is rare to see dead individual swifts, and most of them are scattered in the mountains and seas. In addition to the long distance, there are also various predators waiting for opportunities along the way. Some peregrine and other small and medium-sized raptors are always waiting for tired swallows to enter their prey range.
In addition to the predation of natural enemies, even humans are not far behind. Although our country has a tradition of protecting swallows since ancient times, other regions do not have such a common understanding. Just after Beijing swifts traveled thousands of miles to their wintering grounds, local residents had already heard the news and started to take action. Since swifts live in groups in their wintering grounds, large groups of swallows often crowd together, making it easier for locals to capture them.
In areas such as Nigeria, people gather on the top of mountains, holding a large net in their hands, always ready to scatter to the approaching swallows. Under such circumstances, many swifts become human food. If the swallow under your roof does not return next spring, then it is a pity that it may never come back again. Let us remember them with tears.
