-Nesting is not a unique skill of birds, but the nesting technology of birds is unparalleled in the animal kingdom.
There are more than 8900 kinds of birds on the earth. When breeding, the number of eggs is 1, and the number of eggs is 10. The time required to hatch eggs varies from 10 days to several months. How can these eggs not roll away during hatching and be protected from natural enemies? Nest! The Bird's Nest is the safest and most reliable "home" for birds and the warmest cradle for chicks.
No matter what kind of bird it is, nesting is a very huge and arduous "project", which requires painstaking labor. Swallows, sparrows and magpies are familiar "neighbors". They often nest under the eaves of human houses and on the branches of courtyard gardens. Careful ornithologists have made accurate records. During the four or five days of nesting, a pair of grey magpies took nesting materials for 666 times, including 253 dead branches, 254 green leaves 154, 23 grass roots 123, 82 cow hairs and 54 mud balls. A goldfinch's nest weighs only 53.2 grams, but there are 753 nest materials in total.
Louyan, who nests on towers, temples and other buildings, needs to grab small snails and nesting materials such as soil, grass sticks and saliva from the distant river mud beach, and then build a bowl-shaped nest bit by bit, which takes 1 week. Its close relative, Jin Siyan, has well-developed salivary glands, and can build a nest with pure saliva, which condenses and dries as soon as the wind blows, thus building a translucent small bowl-shaped nest. After this kind of bird's nest processing, it is a precious tonic-bird's nest, which has been famous all over the world since ancient times.
The vulture's nest is 2.6 meters in diameter and weighs two tons. Lin Yuyan's butterfly nest can only hold one egg. The pigeon's humble nest is built among cacti, and the prickly cactus has become its natural animal-proof thistle. Before giving birth, arctic wading birds always have to endure severe pain and pull out a lot of feathers to build nests.
The hornbill, a rare bird in the world, chose a natural cave on a tall tree trunk as a nesting site to build a cage nest. Qi Xin, a couple, works together. The male bird frequently carries soil, while the female bird sits in the hole, spits out a lot of mucus from her stomach and mixes it with the mud ball, and seals the tree hole with it, leaving only a hole in front, where she can stick out her mouth. Throughout the incubation period, females are fed by males.
In order to build beautiful new houses to attract their spouses, bowerbirds living in tropical rain forests in Australia always choose secluded places with ventilation and light, sufficient forest space, food and water, and then take branches 20~30 cm long everywhere to build two dense fences on both sides of the cleaned ground, with the middle as an aisle; At the end of the corridor, there is also a "dance floor", and the whole structure is like a small and exquisite courtyard. More interestingly, it also collects colorful objects everywhere, such as flowers and colorful feathers, and displays them on dance floors and fences. Ornithologists have observed that males take away withered flowers and berries every day, replace them with flowers and fruits, and decorate the "small courtyard" with colorful colors.
There are many bird's nests built in very hidden places and disguised. Claudia is a talented disguise teacher. In the litter layer on the surface, she weaved a spherical nest with branch fibers and grass stalks, and then covered it with a lot of moss and various branches and leaves, exposing only an irregular black hole for parents to enter and leave. There is also a kind of buried bird that "nests but doesn't hatch eggs". Its nest is built under the forest. First, it dug a big pit, and a lot of leaves were piled in the pit, which was padded with solid soil. In this way, a layer of leaves and a layer of land are piled up until a large mound with a diameter of 3-4 meters and a height of 1.5 meters is built, and then a hole is dug at the top of the mound and eggs are buried in it. The temperature required for hatching eggs is provided by the fermentation of leaves in the mound.
The structure built by birds to hide eggs and chicks during breeding can gather the laid eggs together and promote hatching; It can also keep warm and protect parents, chicks and eggs from natural enemies.
The nests of the lower groups are simple, and some only dig a shallow pit on the surface without adding any nest materials, such as penguins, ostriches, golden-eyed birds, white-fronted terns and so on. Some only apply a few hay stalks in the pit, such as yellow-footed three-toed quail, gray-headed pheasant and hairy pheasant. The ground nests of pheasants, cranes and geese are more complicated. They use soft substances such as grass, leaves and down, and some can be woven into a disc-shaped nest. These birds lay more eggs in each nest, and the color of the eggs is sometimes very similar to the color of the environment. Most chicks grow early and can move independently soon after hatching.
Some waterfowl, such as snipe, crake, Dong chicken, bony cock, etc., often bend reeds and cattails on the water and weave them into dish-shaped floating nests.
Some birds of prey and climbers nest in tree holes or crevices, such as owls and woodpeckers. Their eggs are mostly pure white, chicks are late, and the incubation period is generally longer.
Most arboreal birds weave nests with branches, grass stems, hairs and feathers between branches, and the nests of lower groups (such as pigeons) are the simplest, with only a few branches spliced into a shallow dish; The nests of herons, falcons and some large birds (such as crows) are mainly made of thick branches, reinforced with soil and lined with soft substances such as twigs, grass stems, feathers and hair to form a pot-shaped nest. The chickens are all late.
Higher birds are good at weaving delicate nests. They mainly use fine grass stems and plant fibers to weave dish-shaped, spherical or flask-shaped nests, and some use spider silk to weave soft materials such as moss and animal hair into elastic felt-like nests. Sparrows and birds nest cleverly and covertly, with high survival rate of offspring, few eggs per nest and late chicks. In the evolutionary history of birds, finches have adapted to the radiation of different ecological environments and formed a variety of lifestyles and nesting methods, which can nest on the ground, tree holes, crevices, aquatic plants, stems, branches, holes in human buildings and so on.
The role of birds in nesting
Nesting is a remarkable feature of bird breeding activities. The breeding of birds generally begins with nesting activities and ends when young birds leave the nest. The role of bird's nest in the reproductive development of birds mainly has the following four points.
(1) Bird's nest can prevent eggs from rolling away and making them pile up in clusters. For birds with large eggs, it is especially important to keep the eggs in a pile. If all the eggs are kept under the body of the mother bird, the embryo can develop at the temperature of the mother bird.
(2) Bird's nest is beneficial for parents to feed their young birds and avoid enemies. Because many birds can nest in very hidden places, plus some camouflage, it is difficult for natural enemies to find their nests. Some birds make full use of their flight advantages to build their nests on cliffs or among tall branches, so that natural enemies can't find them even if they find them.
(3) The nest can keep the optimum temperature for the development of eggs and chicks. For the chicks of late birds, the body temperature is not constant in the first few days after hatching, and it is easy to change with the change of environmental temperature, so parents need to heat them as often as when incubating eggs, and the nest plays a role in slowing down the heat loss. For example, the tree cavity is higher than the ambient temperature 1℃ ~ 7℃.
(4) Nesting behavior is beneficial to the reproductive behavior of birds. Nesting and nesting activities of birds are important factors to stimulate sexual and physiological activities of paired birds. Especially when birds start to build nests or in nests, the signals from visual and tactile organs can promote the accelerated secretion of estrogen in the body through the synthesis of the brain, so that the eggs in the body can mature and be discharged quickly without interruption of reproductive behavior. Many birds can't recognize their nests. As soon as they saw their nest, they went back to hatch their eggs. Even if the eggs in the nest are replaced with glass balls or stones, some birds will hatch eggs regardless. But if its nest is destroyed, the hatching behavior will stop immediately. Wang Chun, secretary general of the Olympic Public Area Management Committee, said that all service facilities in the central area remained unchanged. At the same time, 20 fixed dining spots will be added for the maintenance of 50 mobile dining cars during the Olympic Games.
In addition, there will be 3 medical service stations, 9 tourist consultation centers, 9 fixed toilets and 2 1 temporary toilets in the central area. Add toilets in peripheral parking lots and other places, keep some Paralympic landscape signs, restore Olympic landscape signs and common city signs in the park, and increase the seating for spectators.
At the same time, the Forest Park will also increase retail outlets and commodity varieties, set up tourist parking lots, reserve the number of ambulances and medical staff during the Olympic Games, and increase 30 battery tour buses.
There is no parking lot in the transportation center.
According to Wang Chun, there are 48 conventional buses, and there will be 10 temporary buses and 4 sightseeing routes in the Olympic Village Park, with a total of 62 bus routes. The bus lines passing through Datun Road underground tunnel will continue to pass according to the Games-time operation mode.
Changes in design scheme of bird's nest
Under the premise of keeping the architectural style of "Bird's Nest" unchanged, the new design scheme has greatly adjusted and optimized the structural layout, building cross-section form and material utilization rate. The openable roof in the original design scheme was cancelled, the opening of the roof was increased, and the steel consumption was greatly reduced by optimizing the steel structure. The long-span roof is supported on 24 truss columns with an interval of 37.96 meters. The main trusses are radially arranged around the opening in the middle of the roof, and 22 main trusses are straight or nearly straight.