"A little sugar never hurts anyone." The Doctor admits while he pushes through the crowds and he offers a smile to Andrew. "Oh, I'm sure this isn't an invasion. There's a chance of rain so that's not exactly invasion weather."

Donna and Andrew would notice that some of the sparrows are having a hard time landing and a few are crashing into things. "They're rubbish at flying some of them."

The fact it could end up being something more than just watching animals in the zoo. He zooms in and out of the crowds at the sound of the bleeping sonic in his hand.