birdy back

例句：

1. 1.The bird is perched on the birdy back of the tree.
   那只鸟正栖息在树的鸟窝上。
2. 2.She built a birdy back for her pet parrot.
   她为她的宠物鹦鹉建了一个鸟窝。
3. 3. The baby bird is learning to fly in its birdy back.
   这只小鸟儿正在它的鸟窝里学习飞翔。