He did indeed sense her approach, but that was a given since she made no attempt at stealth. He showed no indication that he knew--she didn't give off any hostility, after all--until she actually addressed him, though. It was less trouble to just ignore people until they engaged him.

He tilted his head slightly, and reached up to scratch his cheek, looking every bit bored and confused at his question. "...You saw a bubble? It's probably popped by now if it's gone through here." He gestured vaguely through the trees. "They're not very durable."

But then, if she asked him that, there was no way that all she really saw was a bubble. No one asked after bubbles. She was probably a bounty hunter.

What a bother.