Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 有七只鹦鹉和一些乌鸦栖息在一棵树枝上。突然发出了一声响声，同样数量的鹦鹉和乌鸦飞走了。现在只剩下两只鹦鹉和一只乌鸦在树枝上，最初有多少只鸟栖息在树枝上？


### Response:
 响声后飞走的鹦鹉数量是7-2 = <<7-2=5>>5
飞走的乌鸦数量是1，意味着最初有5+1 = <<5+1=6>>6只乌鸦
鹦鹉和乌鸦的总数是7+6 = <<7+6=13>>13