How does Richard Atwater use imagery in Mr. Popper's Penguins?

From the text:

The penguin jumped up onto a chair and from there onto the edge of the table, flapping his flippers again to recover his balance. Then he walked solemnly around the table, and between the dishes of food, inspecting everything with the greatest interest, though he touched nothing. Finally he stood still, very erect, raised his beak to point at the ceiling, and make a loud, almost purring sound. "O-r-r-r-r-h, o-r-r-r-k" he trilled.