Animals "regained territory"-this is the "grand scene" that has repeatedly appeared in cities of various countries since the global epidemic of the New Coronary Pneumonia epidemic: wild boars, foxes, wild ducks, deer ... roaming freely on the empty streets after human isolation. Although some wild animals have long become urban “residents”, there are still many difficulties to survive in the city.
This is not alarmist. Recently, as soon as the self-built residential houses with glass curtain walls were installed in Changping District, Beijing, the reflection of the sky was so realistic that the birds could not distinguish them and crashed into the wall.
According to the official website of the US Fish and Wildlife Administration, the glass curtain wall has become the second largest killer of birds, with an average of "killing" 360 million to 980 million birds per year. The British Ornithological Trust estimates that the number of bird impacts on the glass curtain wall in the UK reaches 100 million each year, and one-third of the birds die directly.
Many experts said in an interview with the Science and Technology Daily that with the acceleration of urbanization, in addition to the glass curtain wall, power transmission lines, wind turbines, and highways have also become "reefs" for bird flight.
Fashionable architecture becomes a bird killer
The glass curtain wall of the city building is fashionable and reflects the prosperous modern light. However, this building material that became popular a hundred years ago has now become a bird killer.
During the annual migration season, a large number of migratory birds fly through China, and more than 50 million waterbirds migrate in the “East Asia-Australia Migratory Bird Migration Area” where our country is located every year.
"Birds killed by the glass curtain wall are mostly migratory birds. They are unfamiliar with the terrain, and their flight speed can sometimes reach tens of kilometers. Once they hit the hard glass curtain wall, they hurt their heads, fell from high altitude, and their internal organs He will also be injured. After falling to the ground, the casualties will be very heavy. "Li Changkan, director of Henan Bird-related Fault Engineering Technology Research Center, explained that after birds perceive different signals in flight, they will conduct integrated analysis in different neural regions of the brain. Form an accurate navigation map. Birds can use astronomical phenomena such as the sun's azimuth, stars, polarized light, mountains, rivers, and magnetic fields to determine the direction of migration, and the glass curtain wall will give the bird an illusion.
"The sky reflected by the glass curtain wall is very transparent, which will make birds mistakenly think that it is a real sky. In addition, the sunlight reflected by the glass will cause temporary visual obstacles to the birds, making it too late to avoid; while at night, birds like to face Flying in a bright place, the city lights reflected on the glass curtain wall will also give them an illusion. "Said Ma Zhijun, a professor at the School of Life Science at Fudan University.
Attach reflective strips to reduce the risk of impact
"The glass curtain wall building is lighter than the masonry structure and will not settle; it has a fast construction speed and high efficiency; it has a high land utilization rate, thin floors, and a high rate of housing, which can ease the tension of land use; it can also reflect the blue sky and white clouds. "It adds a lot to the urban landscape." Zhou Qi, a professor at the School of Architecture of Southeast University, pointed out that the total number of glass curtain wall skyscrapers in China currently accounts for more than half of the world.
Zhou Qi said that in order to prevent the glass curtain wall from breaking, the architect will calculate the impact force of the bird flight to resist the collision. If the bird hits the glass curtain wall, it is equivalent to the egg touching the stone. "Due to these problems, the state now discourages the use of glass curtain walls, but there is no explicit ban."
Since the "lethal power" of glass curtain walls on birds is not small, how to help birds avoid "traps"? Li Chang looked at the suggestion and could add reflective strips on the surface of the building to remind birds to avoid. Ding Changqing, a professor at the School of Ecology and Nature Conservation of Beijing Forestry University, suggested that the glass curtain wall buildings should avoid bird migration channels before planning. If the glass curtain wall is not high, you can also try to plant trees nearby to cover it.
Zhou Qi said that although the state does not currently require a bird environmental impact assessment when building glass curtain wall buildings, some city managers have been aware of the problem.
Sanmenxia City, Henan Province is the largest habitat for wintering white swans in China. Every winter, white swans flying from Siberia will overwinter here. Zhou Qi served as an urban architecture consultant in Sanmenxia. He said: "I have done an ecological environmental assessment, and the local government has requested that the construction of high-rise buildings and glass curtain walls be prohibited near the white swan habitat."
Other crises hidden in the city
In addition to the glass curtain wall, other facilities in the city will also become bird killers.
Li Changjian pointed out that birds have a keen vision, but flying in low-light environments such as cloud, fog, night, etc., especially during the migration, it is easy to accidentally hit the power lines and wind turbines.
According to statistics, about tens of thousands or even hundreds of millions of birds die each year by accidentally hitting power lines. "In China, grey cranes and black-necked cranes often accidentally hit power lines near Lhasa and Urumqi," Li Changjian said.
He believes that under bad weather, the bird's line of sight is affected. Once it hits the generator blade, the wings are easily broken, and the probability of death is very high; while the transmission line is generally thin, it is difficult for birds to discover Once hit, it will either be killed or injured by the collision, or the effective insulation distance between the lines will be reduced, resulting in electric shock. “It is recommended that when laying transmission lines, bird experts are invited to do EIAs to avoid bird migration routes or habitats as much as possible. For transmission pole towers or generator fan blades in high-risk areas where bird strikes have occurred, you can spray bright warning colors or you can Reflective streamers of bright colors such as red and yellow are added to the transmission lines to facilitate birds' avoidance. "
Ding Changqing said: "Bird collisions caused by highways, high-speed rail and traffic lights are also worthy of attention." The honeysuckle and other shrubs planted on both sides of the highway will attract birds to gather and forage. When they are walking on both sides of the highway, It can also crash and cause casualties. Therefore he suggested that such shrubs should not be planted on both sides of the highway.