Almost half of the cuckoo species are broodparasites ; these birds lay their egg s in other birds nest (birds of other species). The unwitting host bird feed intruder bird with its own brood.

• 几乎一般的杜鹃都把自己的蛋下在别种鸟类的窝内；而不知情的鸟妈妈会连同自己所生的一同照顾这个入侵者的孩子.