The AI has seen ducks and rabbits. It has build a good enough internal model of "duckness" and "rabbitness" that even more abstract renderings of ducks and rabbits activate the relevant parts of the net. I mean, that's exactly what we want them to do! Figure out the aspects of the input data salient to the classification task and ignore the irrelevant parts.

That said, I the response here is likely filtered and normalized to only include "duck" and "rabbit" classifications; after all the bird looks much more like a seagull than a duck.