How does rhododendron breed?

Grain Rain is the last solar term in spring. The ancients said, at this time, "the cuckoo sings its feathers", and the cuckoo began to remind people that "the grain is coming soon". This is actually their courtship call. Do you know what happened in such a cry?

Some birds do not nest, hatch or brood by themselves, but rely on other birds to complete the task of breeding offspring, and cuckoo (commonly known as cuckoo) is a typical representative. Rhododendron will seize the opportunity to take eggs from other nests, such as reed warbler, thrush, shrike, etc., and lay one of its own eggs in the nest for other birds to hatch. After hatching, the unsuspecting mother bird will take pains to feed the cuckoo chicks out of the instinct of brooding until they grow bigger than themselves. Why do cuckoos lay eggs in other birds' nests?

A bird lays its eggs in another bird's nest and is fed by other birds. This behavior is called reproductive parasitism. At present, it is not known how larval parasitism evolved, but Rhododendron obviously benefited a lot from larval parasitism. First of all, I don't have to build a nest, hatch or brood, which saves a lot of energy and can produce more eggs. Studies have shown that from March to July every year, female rhododendrons parasitize more than 10 eggs in different nests. Secondly, eggs parasitized in other nests have a higher reproductive success rate. Rhododendron usually lives only on one of its own eggs in the bird's nest. Because of its short incubation period, the eggs of rhododendron often hatch first. Cuckoo chicks instinctively push out the eggs and chicks laid by their parents in the same nest and let their parents raise themselves alone, so that they can get more food and have a higher survival rate. On the other hand, Duo brood parasitism also avoids the risk of "putting all the eggs in one basket", and at least one of the young birds can leave the nest alive to ensure racial reproduction.