The reason is: Rhododendron is a typical bird parasitizing in brooding. It doesn't build nests, hatch eggs or feed chickens. These tasks are all done by the adoptive parents of Xiao Du Fu.
How to lay eggs in other nests;
It will carefully look for the bird's nest. After the target is selected, it will make full use of its similar characteristics in shape, size and body color and fly from afar. The flying posture of cuckoo is also very similar to that of raptor rock harrier; Fly very low, turn sharply to the left and right. Occasionally flap your wings loudly to scare the brooding birds. When the brooding bird saw the figure of a raptor flying low in the sky, it was scared to leave home and run for its life. Lay eggs directly.
For nests that are too small or difficult to enter, it will lay eggs first, and then carefully put the eggs among the eggs of other birds with its beak. But before putting their own eggs, cuckoos often take someone else's eggs from their nests (eat them or throw them away).
Rhododendron develops rapidly and often hatches before or at the same time as the nest owner's eggs. Another bird (or egg) was born, supported by its immature wings, and climbed to the edge of the nest carefully. He lowered his head, put his forehead on the bottom of the nest, suddenly leaned back, lifted the chick (or bird's egg) on his "shoulder" and dug it out of the nest. When the foster mother came back, she saw that there was only one chick left in the nest, so she loved the murderer as a pet and fed the little cuckoo more carefully. Little cuckoo plopped, left without saying goodbye and flew away.