Why can't the sparrows catch the sparrows?

The grabbing sparrows are frightened and often refuse to eat, so they can't raise them.This bird is more common in my country. It has 27 different varieties, but the size and color are relatively close. There are 5 types in my country, which is very widely distributed.Because it is very lively and brave, there is no problem for breeding. It is usually placed in a cage, which can prevent escape.