Kestrel, not having any idea who Kenneth was, remained almost (but not entirely) oblivious to his presence. She didn't know he was there, but she was aware that something was, because the bushes were rustling. And she was on her way to the lake, to examine the landscape and congratulate herself yet again on her extremely vivid imagination.
That said, her imagination was making her hungry, and apparently there were mussles that were great for steaming over at the lake, so she also took a basket with her, and a pointed digging stick to help get them. Maybe, while she was at it, she'd find another drift-wood drum that she could haul back to camp and strike out a beat.