Do you know the reproductive development process of birds? The reproductive and developmental processes of birds generally include courtship, mating, nesting, egg laying, incubation and brooding stages, each of which is accompanied by complex reproductive behaviors.
Courtship
The reproduction of birds generally has obvious seasonality, and birds living in our country generally reproduce in spring or summer. During both seasons, birds release sex hormones, which prompt the bird to nest and alter the bird's plumage and song to attract the opposite sex to pair.
copulation
The forms of "marriage" in birds are diverse, and most birds are "monogamous", such as Mandarin ducks, penguins, etc. Some stay together during the breeding period and part ways after the breeding period, such as white cranes, swifts, etc., and some birds will stay together until the young chicks come out of the nest and separate, such as weaving birds, quails and so on. Of course, there are also birds that are only together during mating, such as the hill sandpiper, the shawl hazel chicken and so on.
nest
Most birds nest on their own, while others build nests in a collaborative manner, usually within a few days. The nest can keep the eggs from rolling, evenly accept the body temperature of the parent bird to hatch, and also facilitate the parent bird to feed the chicks. The materials, locations and shapes of nesting by different birds will also be different, compared to kingfishers and sand swallows digging tunnel-like caves on the shore embankment or sandy cliffs to make nests;, Dai Sheng and Mandarin ducks use natural tree holes to make nests, woodpeckers chisel holes themselves to make nests, and domestic swallows and golden-loined swallows use mud to make nests under the eaves.
lay eggs
After the bird has built its nest, it enters the spawning period. Birds mostly lay their eggs at 4 to 5 o'clock in the morning or 2 to 3 o'clock in the afternoon. Most lay an egg in 24 hours, large raptors lay an egg in 72 hours, and vultures even take 120 hours to lay an egg. Birds not only lay eggs at different times, but also in numbers, with small songbirds generally laying 4 to 6 eggs, while Antarctic penguins lay only 1 egg a year. What's more interesting is that some birds will have their eggs eaten or replaced.
hatch
Incubation of eggs is key to the reproduction of birds, and the embryos inside the eggs need to be formed and developed under conditions close to body temperature. In the part of the bird that comes into contact with the egg body, the feathers will fall off to form hatching spots, where the microvessels are developed and the skin temperature is high, which can promote the hatching of the eggs. In general, the hatching of bird eggs is undertaken by the female, and the male is responsible for guarding and feeding, but some birds are jointly incubated by male and female, and a few birds are hatched by males. The incubation period for eggs also varies, with small birds generally taking 13 to 15 days, medium birds taking 3 to 4 weeks, and large birds taking longer, such as wild ducks, taking 24 to 28 days.
brood
After the incubation period expires, the chicks use the temporary protrusion at the tip of the mouth, the egg teeth, to peck out the egg shell. After the chicks break out of their shells, they need to stay in the nest for a period of time to come out of the nest to feed, during this time, the chicks need to be fed by the parent birds, and when the chicks do not have the ability to live independently, the parent birds also have to teach it a lot of life skills.
Although the life cycle of birds is not as long as that of humans, they are extremely complex processes from birth, childbearing to the end of life, and there are still too many mysteries waiting for humans to discover.
This article was scientifically checked by Huang Shaohua, a senior teacher of the second middle school in Chaisang District, Jiujiang City, Jiangxi Province.
This work is the original of "Popular Science China - Scientific Principles One-Point Pass", please indicate the source when reprinting.