Information about "天伊鸟".

The Enlightenment of Birds to Humans

The contribution of birds to mankind is well known. Birds also have a special role, which is that they inspire human wisdom and provide principles and blueprints for humans to explore ideal technical devices or means of transportation. It can be said that birds are human teachers in terms of structure, function, communication, etc., and scientists often need to consult birds for many modern scientific and technological issues.

Eagles soar into the sky, doves soar thousands of miles, and birds can fly freely in the air. How attractive and motivating this is to humans! Legend has it that more than 2,000 years ago, Lu Ban, a famous craftsman in my country, researched and made wooden birds. According to historical documents, more than 1,900 years ago, some people in our country tied bird feathers together to make wings that could glide a hundred steps away. More than 400 years ago, Italian Leonardo da Vinci designed an ornithopter based on his observations and research on birds, trying to use the movement of his pedals to flapping his wings. Later, after many scientists' experiments, people figured out the mechanism of fixed-wing gliding of birds, and realized that the wings must have thick leading edges and thin trailing edges like bird wings to form a curved surface to generate lift. In addition, industry provided lightweight Using high-quality metal materials and high-power engines, the airplane was finally invented in 1903, realizing the human dream of flying into the sky for thousands of years.

Since humans invented airplanes and took to the sky, they have been constantly innovating and transforming airplanes. They have quickly surpassed birds in terms of size, load capacity, and speed. Modern airplanes can fly faster, farther, and higher than any bird. Especially the various aircraft that have appeared in recent years can travel among the stars, which is beyond the reach of birds. Despite this, man-made aircraft are still not as complete and sophisticated as birds in terms of certain flight technologies and aircraft structures, not to mention the energy consumption. For example, the Golden Plover can continuously fly over the ocean for more than 4,000 kilometers while only losing 60 grams in weight. If the aircraft can fly with this efficiency, it will save a lot of fuel.

The wings of birds have many special functions and structures, making them not only good at flying, but also able to perform many "stunts" that are difficult to achieve with current human technology. The little hummingbird is the "helicopter" among birds. It can take off and land vertically, and fly backwards. When sucking nectar, it does not sit on the flower like a bee, but hovers in the air. What a neat flight it was. Building a vertical take-off and landing aircraft with the flight characteristics of a hummingbird has become the dream of many aircraft designers.

The eagle's eyes are extremely sharp. The eagle soaring at an altitude of two to three thousand meters scans the ground with its eyes. It can detect rabbits and mice among many relatively moving scenery, and swoops down quickly to capture them in one fell swoop. Eagle Eye is also sensitive to moving targets and can adjust quickly. It can identify targets accurately. The development of modern electronic optical technology makes it possible for us to study a system similar to Hawkeye, which can help pilots identify ground targets and control missiles at the same time.

The migration distance of migratory birds can range from hundreds of kilometers to thousands of kilometers. However, they always arrive at the destination chosen for generations. This shows that migratory birds have excellent navigation skills. Scientists have already conducted research on these phenomena and believe that birds have good navigation skills because they have their own special sensory organs that can sense and analyze changes in environmental factors in different regions of nature, so as to identify directions and find migration routes. route. Some rely on identifying the position of the sun and use the sun as a directional guide; some rely on identifying the orientation of stars and use astrological navigation; some rely on sensing changes in the earth's magnetic field and use geomagnetic navigation; and some use the earth's gravity field to navigate. After understanding the principles of bird navigation, bionics scientists and designers can imitate and manufacture various small and reliable navigation instruments to contribute to the development of aviation and navigation.

Inspired by Penguin, people designed a new type of car - "Penguin Polar Off-Road Vehicle". This kind of car uses a wide bottom to stick to the snow and uses a wheel scoop to push forward. This not only solves the problem of polar transportation, but also can drive in muddy areas.

In addition, the unique physiological structures and functions of birds also provide many bionics topics for the innovation of mechanical systems, instruments and equipment, building structures and technological processes. Therefore, birds are both friends and teachers of humans. For the future of science and the happiness of mankind, we should also protect birds.

Birds have given mankind many priceless revelations: when people see flying birds in the sky, they think of a machine that can take us to the sky...an airplane; the determination of a mountain eagle at the moment it flies to the ground and steady, making people feel that they can fly down from the sky and land safely; the dragonfly in flight has inspired mankind to create helicopters; the dexterous and silent flight of the owl has transformed the performance of the aircraft; the swan is on the water The elegance of flying made the seaplane come out. Studying Garuda can improve the function of aircraft, studying pigeons can predict earthquakes, etc. Those who are willing to think have gained inspiration by observing birds flying in the sky, and the miracles they have created have benefited us endlessly

The role of birds in nature

The role of birds in nature refers to the status and status of birds in different ecosystems (such as forest ecosystems, grassland ecosystems, farmland, lakes, oceans, etc.) effect.

Birds are important members of the ecosystem and, although they may not have a major impact on productivity, they have a density-limiting effect on the prey they eat. In addition, birds are responsible for transporting seeds and nutrients, participating in energy flow and inorganic material circulation within the system, and maintaining the stability of the ecosystem.

Birds prey on insects and small rodents, and their role in maintaining the ecological balance of nature is not directly perceptible, because the environmental factors involved are very complex and require rigorous experimental design and arduous testing. Field surveys, laboratory work and detailed analysis can lead to more accurate results. In recent years, quantitative research on bird predation and research on the characteristics of bird predation at home and abroad have more appropriately revealed the role of birds in the ecosystem, especially the status and role of insectivorous birds in the forest ecosystem.

1. The predation effect of birds

Birds have strong flying power, fast speed and large range of activities. Moreover, birds are migratory, territorial during the breeding season and after the breeding season. The clustering nature of birds makes the bird community structure very complex, with great fluctuations in species and quantity. This gathering and movement of bird populations can increase their numbers and "clear" or "eliminate" certain prey species in local areas.

Due to the large food intake and fast metabolism of birds, most insectivorous birds do not have cropping ears like grain-eating birds. The rate at which food passes through the digestive tube is also very different, which is different from physiological needs and feeding. The method, feeding season, age of the bird, condition of the bird and the nature of the food itself are all closely related. Differences in food digestibility may cause the ratio of certain foods to be over- or under-estimated during gastrotomy. To compensate for these differences, correction factors are applied when estimating food composition (Table 1). The species and quantity should be identified based on the characteristics of the insect body remnants, the membrane on the larvae's head, the shields on the thorax and buttocks, the thoracic and ventral foot fragments, and the palate remnants.

Table 1 Estimated consumption of 5th to 6th instar spruce leaf moth by birds during the 20-day larval stage and 15-day pupal stage (birds/hectare)

(from Crawford et al., 1983)

Any kind of bird, even at the same time, will never feed on only the same kind of insect. Their food composition includes not only harmful insects, but also beneficial insects and some insects that have been parasitized by other insects, which increases the complexity of analyzing the inhibitory effect of birds on harmful insects. However, some recent findings suggest that birds tend to avoid parasitized insects. In this way, birds and parasitic insects may be complementary rather than competitive. There are also some birds that show a preference for eating certain pests or insect forms. For example, the cuckoo loves caterpillars of various sizes. Some birds like to eat adult insects, which is very important in controlling pests, because the death of the adult stage often has an important impact on the population size of the next generation

The food that birds eat has obvious seasons. sexual changes. When food is scarce in the winter, many insectivorous birds switch to plant foods. The types of food eaten by birds also change during different stages of their life history. During the fledgling stage, even grain-eating birds must feed their chicks animal food such as insects to ensure normal development and survival of the chicks. Generally speaking, the type, state and period of food that birds prey on are consistent with the food resources that nature can provide. This is the result of long-term evolutionary adaptation between birds and the environment

Birds can affect insects Population abundance and dynamics, and likewise insect species and density, also have important effects on bird predation. Most bird species have functional and quantitative responses to prey population density. The former refers to the behavioral changes that occur when predators attempt to attack more prey when prey density increases. The latter is a change in the number of predators caused by an increase in prey density. Changes in numbers can be caused by reproduction or by "invasion." The unique effects of birds' functional and quantitative responses to insect density can be attributed to the "direct effects of birds on insects." Birds can also affect insect populations indirectly, primarily by changing their prey's microhabitats to make them more susceptible to weather, parasitism and possibly diseases and viruses.

Identifying the predatory characteristics of birds and their interactions with prey populations is important for understanding the place and role of birds in ecosystems. Whether or to what extent the density of main prey is suppressed through the predation of birds is also a very necessary parameter for the comprehensive management of harmful insects.

2. The control effect of birds on forest pests

Birds play an important role in preying on many forest pests. Due to space limitations, we only give some more significant examples to illustrate the role of birds in controlling forest pests in various fields.

(1) The direct impact of birds on leaf-eating pests

Pine caterpillars (Dendrolimus spp.) are the main leaf-eating pests in my country. Surveys in Anji, Zhejiang showed that birds in different periods and in different plots had very different predation effects on pine caterpillars (Table 4). During the bird breeding season and forest edges, the predation effect can reach 18.5% and 22.2%, while in other plots it is only 4.7%. After the breeding season, in the same forest edge, the predation effect dropped to 8.7%, which was about 1/3 of the breeding season. In Zhangpu County, Fujian, the predation rates of insectivorous birds on pine caterpillar larvae above the fourth instar were 19.73% (3rd generation) and 48.75% (4th generation) respectively. Among the predation effects of various natural enemies, insectivorous birds have the greatest control effect on pine caterpillar populations.

By studying the fertility of great tits, the composition of nestling food, and the proportion of pine caterpillar pieces in the food, it was found that as the population density of pine caterpillars went from high (1985) to low (1987), and then gradually increased (1988) Periodic changes, the proportion of pine caterpillar food pieces in the nestlings' food also changes accordingly (Table 5), the average number of eggs and chicks in the clutch has an increasing trend, and the start of the breeding season is significantly earlier (Table 6), showing obvious Functional and quantitative responses. It is worth noting that when the population density of pine caterpillars is low, although the density of the great tit breeding population, the number of nests, and the proportion of pine caterpillar pieces in the chicks' diet also decrease accordingly, the predation effect increases compared with when the population density of pine caterpillars is high. 11.24 times.

Table 4 The number of pine caterpillars inside and outside the bird-proof fence (from Chu Guozhong, 1987)

Table 5 The average daily ratio of pine caterpillars in the food of the first batch of great tit chicks< /p>

(From Chu Guozhong, 1989)

Table 6 Annual changes in fertility parameters of the first batch of great tit chicks

(From Chu Guozhong, 1989) 1989)

The spruce leafroller (Choristoneura burnijerana) is the most important defoliating pest in North American boreal spruce-fir forests. Some people estimate that in the decline stage after a large outbreak of leaf rollers, birds consume about 13% of the larvae. When the number of leaf rollers per hectare is 1,235,000 to 2,471,000, the degree of bird control is 3.5 to 7%. Others have analyzed the stomach contents and found that under conditions where leaf rollers occur, 40% of the food in bird stomachs is leaf rollers. The results of the 4-year analysis showed that the proportion of leaf roller moths in the bird stomachs was 7 to 46%. When leaf rollers occur in large numbers, birds respond both functionally and quantitatively. Birds that originally fed on the ground, tree trunks and grass seeds changed their feeding habits. For example, orange-capped thrushes, meadowlarks (Junco spp.), woodpeckers and crossbills began to eat the eggs and pupae of leaf rollers. Several warblers showed the largest population response. Although the number of some warblers decreased, the number of chestnut-breasted warbler (Dendroica castanea) increased 12 times, and the number of orange-breasted warbler (D. fusca) increased 9 times. Of course, leafroller density increases 8,000 times when large numbers occur.

When Choristoneura pinus develops to 4 to 5 years old, many birds change their feeding habits and begin to feed on this rich food. Predation occurs after the mature larvae and until the pupal and adult stages. In the second year, a large number of blackbirds entered the 240-hectare plot. At that time, there were about 24,700 pine curlew moths per hectare. The predation role of the birds increased from 40 to 45% in the first year to 60 to 65% in the second year. . The number of chickadees that feed on winter inchworm (Operophtera brumata) larvae is relatively low, only 0.3-2.6%, but they feed on about 10% of the emerging adults, mainly females, which is equivalent to 20%. Adults are preyed upon. In Hungary, house sparrows and tree sparrows can kill more than 98% of adult insects and may play an important role in controlling the American white moth (Hyphantria cunea). In Japan, tree sparrows and gray starlings (Sturnus cineraceus) kill about 40 to 50% of American white moths that appear before dusk. Since the mating activity of this moth occurs from sunset to sunrise, bird predation causes Mortality may have important consequences for the population dynamics of this insect. While studying chickadees and Regulus regulus, someone found that great tits regularly feed on Ernarmonia conicolana larvae on young forest cones. The intensity of predation varies with the density of larvae in the cones, and there seems to be a critical value. (10 larvae per 50 cones). Exceeding this critical value is conducive to bird predation. Although great tits may eliminate more than 50% of overwintering mature larvae, the population still grows the following year.

(2) Direct and indirect effects of birds on bark beetles

Woodpeckers are the main predators of bark beetles. There are mainly hairy woodpeckers (Dendrocopos villosus), downy woodpeckers (D. pubescens) and three-toed woodpeckers (Picoides tridactylus). They exhibit both functional and quantitative responses. Quantitative responses are particularly important, especially in local areas. A 50-fold increase in woodpecker density has been recorded in a woodland burned by fire, and this aggregation sometimes exceeds the increase in silverfish in small patches of woodland. When red-winged beetles (Dendroctonus, ru-fipennis) generally occur, the feeding amount of woodpeckers is 20-29%. When the density is from medium to high, they can be eliminated by woodpeckers feeding themselves and other methods (such as bark drying) 24-98% of silverfish. Woodpecker feeding activity can promote bark desiccation. In addition to woodpeckers, eight other bird species preyed on 10% of adult red-winged beetles. The number of woodpeckers preying on D. frontalis ranges from 5 to 86%. Such differences in the results reported in different areas may be due to differences in climate, outbreak extent and process, and the number of generations that occur each year, and thus the impacts caused by woodpecker feeding activities are also different.

After the outer bark is pecked off, the remaining bark dries quickly and is more susceptible to adverse weather and disease. This mortality rate is often greater than that eaten by woodpeckers.

There are 11 species of birds in 4 families that feed on D. brevicomis. Six species of birds (excluding woodpeckers) preyed on adults, and the predation rate in 3 years ranged from 8 to 26%. Hairy woodpeckers, downy woodpeckers, North American black woodpeckers (Dryocopus pileatus), and white-headed woodpeckers (Picoides albolervatys) are the most important predators of western pine beetle larvae in the central California Sierra. In the early stages of the outbreak, the predation rate was 32%. Woodpecker populations increase in large occurrence areas. Initially due to immigration and later due to tree death increasing the availability of woodpecker nest sites and roosts. When woodpeckers look for beetles, they need to peel off, pierce or make holes in the bark. The bark peeled off by woodpeckers contains a considerable number of beetle eggs and about 58% of larvae, which all die in winter. After being pecked by woodpeckers, the bark becomes thinner, and the temperature and humidity are very different from the original bark, which reduces the protective effect of the bark on the remaining small beetles and also creates opportunities for parasitoids with short ovipositors to lay eggs. All of these The indirect effects are increased death of beetles (see figure).

(3) The direct impact of birds on stem-boring pests and weevils

Woodpeckers are also the main predators of stem-boring pests. The predation rate on the larvae of Tiger Oak Longhorn (Goes tigrinus) can reach 32% and 65%, and the predation rate on Beech Longhorn (G.pulverulentus) larvae can reach 39%. Larval predation rates on Saperda calcarata were 13% and 65% at the two study sites. It has also been found that 98% of the spotted woodpecker's diet is the larvae of the aspen beetle (Saperda carcharias), and it is estimated that this larvae can be reduced by 12%. Woodpeckers are also the most important natural enemy of the lilac borer (Podosesia syringae), causing 67 to 81% mortality of this insect. In the Netherlands, woodpeckers show functional and quantitative responses to wood borers (Pissodes piniphilus). When the population of woodworms is low, the amount of predation by woodpeckers is smaller. As the number of woodworm larvae increases, 95% of the larvae and pupae may be eaten by woodpeckers, especially during the food shortage stage. However, wood beetles at the base of trees often cannot be preyed upon.

(4) Spread of bird and insect pathogens

It has been proven that birds can spread insect pathogenic viruses by feeding on infected insects. Of the 49 piles of guano collected from the trees, 44 were infectious, and 89.9% of the larvae tested were infected with nuclear polyhedrosis virus (NPV) and died. Birds are passive carriers of the virus. In winter, the virus can be spread at least 6km away from the center point. Of course, due to different climate and other conditions, not all eaten bird droppings infected with insects are active.

In short, the forest is an important living place for birds. Both birds and pests are members of the forest ecosystem. In the long-term evolution and natural selection, a complex predator-prey system is formed. Birds are predators. An important component of the hunter-prey system. Stochastic predation by birds can exert functional control in ecosystems and have an important impact on the population dynamics of many forest insects. Birds are not only the direct death factor of pests, but can also indirectly affect pest populations by spreading insect pathogenic microorganisms or affecting parasites and predators by changing microhabitats. When pest population densities are low or at increasing densities, the effect of birds in reducing pest numbers is much greater than when pest populations occur. The main function of birds is to block or prevent the occurrence of pests, or to lengthen the interval between major occurrences. However, birds alone cannot disrupt widespread pest populations. When pests occur, the birds' reproductive potential, feeding habits, and territorial relationships reduce their influence as predators. If the occurrence of pests is small-scale, due to the invasion of resident birds or the influx of large flocks of migratory birds, birds can also play a controlling role and accelerate the decline of pest populations that have reached their peak.

3. Other functions of birds

Birds of prey (eagles, owls, falcons, eagles, etc.) often feed on rats in forests, grasslands, and farmland. Some corvids and shrikes can also prey on rodents, and together with other natural enemies, they suppress rodent populations. In a structurally intact forest environment, natural enemies can suppress and delay rapid increases in rodent populations, and can also reduce the density of increasing rodent populations. Someone found 1,348 rat carcasses in the stomachs of 360 buzzards. Someone studied 19,000 owl food balls and found 46,179 small mammals, almost all of them rats. A five-year study on the long-eared owl's food habits confirmed that its main food is rodents, with only 1.3% being small birds. An analysis of the food scraps of overwintering long-eared owls in Wuchang, Hubei Province, found that 70.3% were small rodents, mainly Apoderma agrarian. From 1982 to 1986, 923 food pieces were collected from 58 Strix nebulosa nests, of which voles (Microtus spp.) and flat-toothed cyst rats (Thomomys talpoides) accounted for 52% and 29% respectively.

Many birds, especially birds of prey such as vultures and owls, as well as seagulls, crows, etc., have the habit of eating carrion. They make special contributions in eliminating diseased animals and decaying carcasses, and eliminating organic matter that pollutes the environment. Birds eat insects that parasitize their larvae inside and outside livestock, and starlings and tick-eating birds can eliminate ticks and other parasites that threaten livestock and wild animals.

Many birds are pollinators of flowering plants, especially some tropical birds, such as hummingbirds, nectar birds, sunbirds, flowerpeckers, whiteeyes, bulbuls, fulmars and parrots. It is an important pollinator of certain flowering trees and shrubs. Without these birds, the ecological balance of nature could be seriously disturbed. In addition, many birds have the behavior of storing seeds. Jays usually hide cones under leaves, moss, and stones. A group of jays (about 30 to 40 individuals) once collected 200,000 pine cones and carried them 1 km away. There are 7 species of doves in the low-humid forests of the Malay Peninsula that feed on at least 22 species of banyan tree fruits. Green doves specialize in the seeds of fig trees and disperse the seeds far away through defecation. Birds can disperse seeds over short or long distances, and many migrating birds still have viable seeds in their digestive tracts and may disperse over slightly greater distances. It has been shown that certain hard-shelled plant seeds germinate more easily after passing through the digestive tract of birds. Some insectivorous birds, such as three-toed woodpeckers (Picoides spp.), thrushes, chickadees and chickadees are also important seed dispersers. The oak woodpecker (Melanerpes formicivorus) digs holes in various trees and wooden poles and fills the holes with nearby cones. Not all cones stored by birds can be recovered by them, and these forgotten fruits are often a reason for forest expansion.