It is for birds.

When Lucy was a baby, every time she droped some food like bread rice on floor, we would pick up, and threw them in the garden, and told her, " It is dirty now for birds. " Then she started to do that herself, when she dropped some food accidently.

Then she became quite picky with her food, she will drop the food which she doesnot like on the floor, says " oppsy, It is dirty now, for birds. " Hmmmm .

Today after we cam back from the shop in the village, Lucy was eating her bread roll, and she droped on the pavement accidently. I said to her, "Don't worry , it is dirty now, mummy got the another one in the bag. "
Lucy said, " It is for birdies, mummy why do bird eat the dirty bread? I don't eat it. Are they naughty birds? "