# swallow

By [the sky](https://paragraph.com/@the-sky) · 2022-04-01

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Swallow is the general name of 74 species of birds of passerine family. Small shape, narrow wing tip, concave tail, short beak, weak feet, not too many feathers. The feather coat is monochrome, or blue or green with metallic luster; Most species are similar in both sexes. Swallows spend a lot of time catching pests in the air. They are one of the most flexible finches. They mainly feed on mosquitoes, flies and other insects. They are well-known beneficial birds. Nest in tree holes or cracks, or drill holes on sand banks, or stick mud to the walls or protrusions of corridors, roofs and eaves in urban and rural areas.

Almost all yanidae species only eat invertebrates in the air, mainly insects. Plant food is only found in a few kinds of food, and the intake is very small. Only two-color tree swallows regularly ingest plant substances (mainly berries), which only occurs during insect scarcity. Swallows are not opportunistic predators. They don't fly around aimlessly and eat plankton randomly into the air with their mouths open. Instead, they take the initiative to prey on specific prey. The species distributed in the same domain are often specialized to prey on invertebrates of different body types. For a certain kind of individual, it often chooses the largest prey it can get. The food of migratory bird species in winter is usually different from their food in breeding grounds. For example, when the domestic swallow winters in Africa, the proportion of ants in food will increase. In addition, the preferred foraging degree of a species will also be different in winter and breeding sites. These changes are considered to be the result of competition between these migratory birds and resident bird species in winter areas.

![](https://storage.googleapis.com/papyrus_images/692472bd612965a114933761056942953290aa60926cb65a1ca570e9930b3a69.png)

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*Originally published on [the sky](https://paragraph.com/@the-sky/swallow)*