crow
The "fierce character" in the bird
If you ask what black birds are in the city, quite a few readers will blurt out: Crows! Indeed, at least four of the dozen or so species of crows distributed in Beijing are common black-type crows, which are black all over the body, move in groups, and have a unique social nature. Crows are still opportunists, in the search for food and defense against predators are also good at teamwork and coordination, even for many large birds of prey also dare to harass and tease, full of black more "fierce" temperament, the following is the introduction of beijing common four kinds of black type of crows.
Adapt to the city's large-billed crows and small-billed crows
Large-billed crows (Corvus macrorhynchos) is one of the common crows in Beijing, they are 57 cm long, they are stout medium and large crows, their heads and beaks are very thick from the side, also known as thick-billed crows. The forehead and the base of the beak are right-angled. Dead animals, dead fish and birds of prey discarded by birds of prey in winter are all foods they can easily obtain, and it is this thick beak that makes them experts in pecking at animal carcasses, and even in the cold winter, the frozen hard corpses will slowly crack under the tearing of their thick beaks, and they will be pulled out and eaten by them little by little. Large-billed crows also rely on herds to drive away large birds of prey such as giant eagles and sea eagles, and take their food to enjoy themselves. The call of the large-billed crow is a thick wa, wa monosyllabic sound.
Wild big-billed crows active in zoos
The small-billed crow (Corvus corone) is similar in size to the large-billed crow, with a body length of 55 cm, but its larger-billed crow is smaller and its beak is more pointed, which also gives them the name of the slender-billed crow. Small-billed crows have more vibrato when they call, and larger-billed crows have slightly longer wa and wa calls. Although the small-billed crow is not as large as the large-billed crow, it is more ferocious than the large-billed crow. In addition to looking for animal carcasses, they also actively attacked everything they had the opportunity to catch, and I once witnessed four small-billed crows attacking the young birds of a night heron in the zoo, and in just a few minutes, a night heron larger than a crow was eaten by them.
Small-billed crows search the frozen waterways for food discarded by tourists
These two species of crows are common in parks in downtown Beijing, zoos are also their favorite shelters because there is an abundant food supply, food discarded by people is their target, and another important food source is meat feed that cannot be eaten by carnivores raised in zoos, where there is a real sense of the wild.
Bald-nosed crows and red-billed mountain crows living outside the city
Inside the city, the large-billed crow and the small-billed crow are highly adapted to urban life, while the bald-nosed crow, especially the red-billed crow, prefers the sparsely populated suburban farmland and mountain environment, which are more obvious in the agricultural land and mountainous areas on the outskirts of the city.
The bald-nosed crow (Corvus frugilegus) resembles a small-billed crow, but is more significantly elongated than the small-billed crow, with a body length of 47 cm, and the length of the wings is comparable to the length of the tail when standing, giving people a visual feeling of a short tail. Adult bald-nosed crows have no nasal feathers around their upper beaks and are grayish-white at the base of their upper beaks, which look gray from a distance. Sub-adults of small-billed crows also have nose feathers, but the shape of the beak is more conical and slender.
Bald-nosed crows love to move in the open and often stop at buildings
Unlike the large-billed and small-billed crows, bald-nosed crows prefer the agricultural land and shallow mountain environment around the city, they are rare in the hustle and bustle of the city center, and they can often be seen in the farmland, reservoirs and other environments outside Beijing in winter, they will dig up insects dormant at the roots of plants for food, and will also group with large-billed crows, small-billed crows and Dauri crows.
The red-billed mountain crow (Pyrrhocorax pyrrhocorax) is the smallest pure black crow seen in the Beijing area, with a body length of 37 cm. The red-billed mountain crow is dark in color, the most notable feature is its red and slender beak and red feet, and its long beak is suitable for rummaging through grass and cultivated land for insects such as grasshoppers, grasshoppers, and golden turtles. They are distributed in the mountainous environment of northeast to southwest China, distributed in the surrounding mountains in Beijing, and rarely enter the city, so they are rarely seen in urban areas.
Red-billed mountain crows that live in the inter-mountain meadows, and grassy insects are their favorite food
Red-billed mountain crows mostly live in pairs, and during the breeding period, their nests are in caves or crevices on mountain cliffs, and red-billed crows can often be seen in pairs or small groups at high altitudes using air currents to fly and play in valleys. The red-billed mountain crow has a yellowish beak during the juvenile period, resembling that of its close relative, the yellow-billed mountain crow, but the yellow-billed mountain crow's beak is obviously shorter and thicker than that of the red-billed mountain crow, and it is not difficult to distinguish them with a little attention.
Group activities Team wins
These crows have also evolved a tacit team, even if different species will have swarm activities, they will forage together, find predators together, harass and drive away medium and large birds of prey, and even many bird watchers see birds in the wild when they are "discovered".
There are at least a dozen species of birds of prey that can be seen in the winter in Beijing, and in the wild environment, these crows will always stare at the birds of prey and report each other's safety. What is more interesting is that they can make different alarm sounds for different birds of prey by observation.
The alert frequency of individuals responsible for whistles when small birds of prey such as kestrels and sparrowhawks are spotted is relatively slow, because many small birds of prey are not as large as them and have no chance of causing them any harm in terms of strength and speed. The sentry individual seems to tell his companions: There is a small bird of prey, everyone can pay attention! At this time, some good individuals will even catch up with them for a harassment chase, a very enjoyable look.
When you find the fast-flying peregrine falcon, the falcon hunting falcon, and the goshawk that combines speed and flexibility, their warning calls are faster and louder, as if to tell their companions: there is a more fierce role, everyone hurry to pay attention, be careful of being attacked! Usually when this happens, other kinds of people who hear the warning sound will also make the same call together, and the early warning sound will become larger and louder, more and more. This phenomenon is both a response to their companions and a deterrent to predators, but they are still extremely afraid of these birds of prey who are known for their speed and strength.
Sea eagles eat fish, and I come to watch
When large birds of prey such as steppe eagles and white-tailed sea eagles are found, they will even choose to watch. There are two main reasons, one is that the large birds of prey are large, the speed of flight is relatively gentle and lack of flexibility, can not make a small radius of sharp turns, these crows are significantly smaller than the size of large birds of prey, more flexible and maneuverable, large birds of prey will also be powerless to harass the crows, can only choose to stay away. In addition, crows like to watch and harass large birds of prey because they may get food from them, and when there are large birds of prey, it may be the time when they catch prey, whether it is to drive away the birds of prey or wait for it to leave after a full meal to eat free food, they will not give up this opportunity easily.
Adapt to each other inside and outside the city
In downtown Beijing, crows are one of the common birds, and the public is still relatively familiar with them. In fact, as early as the Qing Dynasty, the reason for Manchu customs and beliefs did not regard the crow as a symbol of ominousness and obscurity, but loved it very much, and when it was outside the Guanwai, a solon pole was set up in the courtyard for worship, and the tin bucket at the top of the solon pole was used to hold pig offal and broken rice to feed the crow. After entering the Central Plains, this custom was brought to Beijing, and today the Solon pole can still be seen outside the Kunning Palace in the Palace Museum in Beijing, but feeding the crows has long stopped, but this does not affect their lives in the Forbidden City and beijing.
Modern Beijing urban area with urban construction and human activities, still provides convenient conditions for many crows, the heat island effect generated in the winter city leads to higher urban temperatures than outside the city, some parts of the urban area such as the North Normal University have become the crows night habitat, in addition to the city such as the park people feed the stray cat food, and tourists discarded food also provides a stable food supply for the crows, which is the main reason why they enter the city and live in the city for a long time.
The large-billed crows and small-billed crows living in the city have adapted to the life with people since ancient times, and have long been familiar with human activities and human existence, while outside the city, bald-nosed crows and red-billed mountain crows have long been adapted to living with people, and human beings in farming, production, animal husbandry, and life also provide them with the convenience of survival. Many wild animals do not contradict human activities, on the contrary, many wild animals can also transform the impact of human activities on nature and the environment into favorable living conditions for themselves.
Author: Zhang Tongtong
Editor, Proofreader: Wei Yao