In rural areas, sparrows are one of the most common birds. They are active in front of and behind houses, living in groups, and can be seen everywhere throughout the year. Sparrows are mostly distributed in urban and rural areas with large populations, and are closely related to human production and life.
Perhaps because they are too familiar, people lack understanding and observation of the living habits of sparrows. One detail caught everyone's attention: there are many sparrows in rural areas, but people rarely find sparrow remains. Why is this?
Sparrow: Mainly feeds on pests, and overall it is a kind of beneficial bird
First of all, let's understand the living habits of sparrows, which is related to the "reputation" of the sparrow population. Sparrows in my country are known for their numbers, and there seems to be no survival crisis. However, in history, sparrows were hunted on a large scale as one of the "four pests". It was not until after in-depth research on the living habits of sparrows that people discovered that sparrows should be classified as beneficial birds, which is reflected in their diet.
From the 1950s to the 1980s, Chinese scholars did a lot of work on the feeding habits of sparrows. Except for Yunnan-Guizhou and Qinghai-Tibet, the feeding habits of sparrows have been reported in almost all parts of the country. The more consistent view is that during the breeding period from March to August every year, sparrows mainly eat insects and other animal foods, most of which are agricultural pests. According to a survey by Guo Ling and other scholars, the food proportion of pests is as high as 93%. During the non-breeding period, sparrows eat grass seeds as their main food. During the wheat ripening season and autumn, there is a phenomenon of stealing grains. At this time, a large number of crops are mature, and the sparrows' food habits begin to change from meat-based to vegetarian.
Throughout the life cycle , sparrows do not exclusively eat food. They feed on insects most of the time and can eliminate a certain number of pests in summer. According to expert estimates, each sparrow can eat an average of 211.2 grams of insects from May to August. The insect-eating amount of young birds is even more considerable. The insect-eating ratio is 3.8 times that of adult birds. Moreover, the number of young birds is more than twice that of adult birds, and the control effect on pests is more obvious.
Sparrows have certain ecological and economic value, are of great benefit to the growth of crops, and are conducive to stabilizing the balance of farmland ecology. This is why my country has removed sparrows from the "four pests" and classified them as three endemic animals.
How many years is the natural lifespan of a sparrow?
"Although a sparrow is small, it has all five internal organs." As the most typical small bird, the life span of the sparrow has also attracted much attention. Many people think that sparrow corpses are rare because sparrows have a long natural lifespan and not many sparrows die every year. However, scientific research proves that the truth is not that simple.
Sparrow is the collective name for 27 species of finch birds. Common ones in China include house sparrows, mountain sparrows , and tree sparrows. Different finch birds have different natural life spans. According to a study in the United States, the average life span of sparrows in the natural state is only about 113 years. The life expectancy of house sparrows can reach 113 to 5 years. The average life expectancy of rock sparrows is 112 to 5 years.
Saltmarsh Sparrows
The above are not the longest-lived sparrows known. American scientists discovered an old sparrow in Texas in 2004. Its age reached 15 years and 9 months. It is considered a "super longevity" among wild sparrows. The lifespan of captive sparrows can be even longer. The longest recorded record is 23 years. However, long-lived sparrows are just an exception, and the vast majority of sparrows will hardly die.
This is because sparrows have many difficult natural enemies, such as: stray cats, snakes, squirrels, crows and small raptors. These predators all prey on sparrows. Among them, the most noteworthy are stray cats. In 2013, the Smithsonian Research Institute in the United States established a research model on the feeding habits of stray cats and found that approximately 1113 to 4 billion birds are killed by stray cats in the United States every year, most of which are sparrows.
Another reason for the death of sparrows is climatic factors, and every winter is a huge test. Scientists have found that skinny young sparrows are more likely to die than adults during the winter. Firstly, this is because the wings of young sparrows are thin, and the low temperatures in cold winter may directly freeze to death or frostbite the sparrows, resulting in a reduced survival rate; secondly, rain and snow in winter reduce food sources, and sparrows are prone to starve to death because they cannot find food; thirdly, during winter foraging in groups, fights within the sparrow population become more frequent, and in severe cases, vulnerable sparrows can be injured and die.
In addition, disease infection, deterioration of the ecological environment, use of pesticides and insecticides, and human hunting activities also threaten the natural life span of sparrows. Therefore, it is not easy for a sparrow to live for three years in the wild. The period is full of challenges. Being over 10 years old is almost a miracle of life.
There are many sparrows in rural areas, and their mortality rate is very high. Why are sparrow corpses rarely found?
There are a large number of sparrows in our country. Each pair of parent sparrows can breed 12 chicks a year. However, the sparrow population has not developed to the extent of flooding. Behind this lies the extremely high mortality rate of sparrows. A foreign survey shows that for every 10,000 sparrow eggs, an average of 1191.86% of the sparrow eggs can hatch successfully, but only 11588 of the young sparrows can survive the first winter of their lives, of which 11312 of them can survive until the second autumn. The average survival rate in the first five years is only 0.56%.
So, where does the remaining body of the sparrow go after it dies?
In fact, many sparrows are directly eaten by natural enemies. Sparrows enter the digestive tract of predators as prey and participate in the material cycle of nature. This is no different from other animals in the ecological chain. For example: after a sparrow is eaten by a cat, only a messy feather may be left, and the sparrow's body will naturally be traceless.
Even if they survive predators, the remains of sparrows will be broken down by decomposers in nature. Compared with other animals, sparrows are lighter in weight, have thin skin, less fat, and hollow bones. Their density and weight are much lighter than mammals of the same size. So when a sparrow dies, the remains are quickly decomposed by small decomposers such as bacteria and insects, and the entire process usually only takes a few days to complete. In addition, weasels , cats and other carnivorous animals can also detect dead sparrows in time through sniffing and dispose of the bodies as soon as possible.
From the appearance, the sparrow's feathers are not brightly colored, with a brown tone. After death, they are hidden in grass, shrubs or dead leaves and are difficult to detect. In addition, most sparrows die in places with low human activity, such as fields, mountains or inconspicuous roadsides. This is why people rarely notice sparrow corpses.
The last reason is related to the living habits of sparrows. According to the observations of zoologists, adult sparrows enter caves to spend the night soon after autumn begins, such as bird nests under the eaves, abandoned nests of swallows, etc. Northern In early winter, sparrows compete fiercely to grab caves. Some nests are not well kept warm, and sparrows may freeze to death in their nests during the winter. In this case, the carcass of the sparrow will not be discovered.
Summary
Sparrows can be seen everywhere in rural areas, with large populations and strong reproductive capabilities. However, after death, sparrows rarely appear in human sight. This is because sparrows are at the bottom of the food chain and are easily eaten by carnivorous predators such as minks, cats, and snakes, and it is difficult to leave carcasses and remains behind.
At the same time, sparrows are small in size and light in weight, and their bodies will be completely decomposed by microorganisms in a short period of time without leaving a trace. This is why the fossil record of birds is so scarce. Coupled with the concealment of the place of death, people naturally rarely find the corpses of sparrows.
