This little sparrow-like creature is more skillful than a human in cracking melon seeds.

A cold wave brought snow and wind from Siberia, bringing winter and a flock of sparrows.

What kind of animal is a swallow? The name of the swallow may remind people of the sentence in Zhuangzi: "How can a swallow know the ambition of a swan?" In fact, this ancient Chinese sentence refers to the general term for two birds, swallows and "house-crafted" (sparrows). The swallow mentioned here is actually a sparrow with a swallow's tail (the same order as the sparrow, Passeriformes).

In the eyes of the public, if there are brown and black birds flying past us, we will mistake them for sparrows if we are not careful, not to mention that they are almost the same size as sparrows. Of course, if we look closely, we can find some clues from the appearance and color matching.

Sparrow | Photo provided by the author

The biggest feature of the sparrow is the black "dimples" - the black feathers on the cheeks. Other birds of the same size do not have such features. The sparrow's brown feathers are relatively uniform, while the body color of the sparrow is black and yellow, so it has the nickname "budgie".

The male and female swallows look different. The male swallows in the breeding season have black heads and black brains, which are very easy to recognize. But in winter, which is the main time period when they come to our place, the male bird's "makeup" will be relatively elegant, retaining a hint of black, which can be slightly distinguished from the female bird. The female bird's head is relatively dark, with brown as the main color, not as bright as the male bird.

Female swallow | Photo provided by the author

Every year when winter comes, the swallows migrate from their breeding grounds in Russia to our country, chasing the cold wind. They come in groups, and a migration group can reach thousands. They can be seen in most of the provinces with relatively dense populations in our country, especially in North China. Perhaps it is because the fallen leaves expose the active swallows, or it may be because they can find enough food to survive the winter in North China, making them unwilling to spend too much effort to migrate south. Therefore, the migration happens quietly. It seems that overnight, these birds fill every corner of the city, and in the following winter, they become a group of lively elves in the deserted city parks.

What do the sparrows eat in the seemingly barren winter? Take Beijing for example. Although there is not much green in winter, there are still many rich foods for them to choose from. The fruits of the common white wax tree in greenery are their favorite food. Every winter, when the leaves fall, the fruits on the trees appear, and so do the sparrows.

These are the fruits and seeds of the white wax tree. Do they look familiar to you? | Photo provided by the author

Although the swallows have small beaks, they are very skillful and orderly in cracking the seeds of the ash fruit. They first bite off the wings of the ash fruit, then turn the fruit over, constantly feel the stress points of the fruit, and crack the seeds out of the fruit. The hard fruit skins fall all over the tree, just like us cracking melon seeds. Sometimes when "picking" ash fruit, the fruit that accidentally falls will float down, indirectly helping to spread the seeds.

Finished white ash seed shells |

Like sparrows, they often search for various plant seeds that have fallen in the grass in groups, such as seeds of foxtail grass. Therefore, what we often see in the green belts in winter may not be sparrows but finches. What is even more surprising is that in one observation, it was found that these little guys would do some "bad things" - several finches gathered on the tree trunks to suck the sap flowing from the wounds of the trees. It may be that the woodpeckers pecked the trees and they also used it, or it may be that they did a good thing. I wonder if the sap is more delicious to them than other foods.

A swallow picking up grass seeds to eat on the ground | Photo provided by the author

Around the end of March, when spring returns to the earth, the sparrows in the city, which were originally scattered into several small groups, begin to gather into a large group and set sail again, returning to the distant Siberia. Before officially setting off, many male sparrows have already begun to change into the breeding feathers needed to find a mate - a conspicuous black feather.

A gust of south wind blew, bringing warmth and also blowing away the swallows and sparrows.

This article is produced by the Science Popularization China-Creation Cultivation Program. Please indicate the source when reprinting