The Secret Garden

Based on the final paragraph of the supplied extract:

At first the robin watched Mary and Colin with sharp anxiety. For some mysterious reason he knew he need not watch Dickon. The first moment he set his dew-bright black eye on Dickon he knew he was not a stranger but a sort of robin without beak or feathers. He could speak robin (which is a quite distinct language not to be mistaken for any other). To speak robin to a robin is like speaking French to a Frenchman. Dickon always spoke it to the robin himself, so the queer gibberish he used when he spoke to humans did not matter in the least. The robin thought he spoke this gibberish to them because they were not intelligent enough to understand feathered speech. His movements also were robin. They never startled one by being sudden enough to seem dangerous or threatening. Any robin could understand Dickon, so his presence was not even disturbing.

But at the outset it seemed necessary to be on guard against the other two. In the first place the boy creature did not come into the garden on his legs. He was pushed in on a thing with wheels and the skins of wild animals were thrown over him. That in itself was doubtful. Then when he began to stand up and move about he did it in a queer un accustomed way and the others seemed to have to help him. The robin used to secrete himself in a bush and watch this anxiously, his head tilted first on one side and then on the other. He thought that the slow movements might mean that he was preparing to pounce, as cats do. When cats are preparing to pounce they creep over the ground very slowly. The robin talked this over with his mate a great deal for a few days but after that he decided not to speak of the subject because her terror was so great that he was afraid it might be injurious to the Eggs.

When the boy began to walk by himself and even to move more quickly it was an immense relief. But for a long time—or it seemed a long time to the robin—he was a source of some anxiety. He did not act as the other humans did. He seemed very fond of walking but he had a way of sitting or lying down for a while and then getting up in a disconcerting manner to begin again.

One day the robin remembered that when he himself had been made to learn to fly by his parents he had done much the same sort of thing. He had taken short flights of a few yards and then had been obliged to rest. So it occurred to him that this boy was learning to fly—or rather to walk. He mentioned this to his mate and when he told her that the Eggs would probably conduct themselves in the same way after they were fledged she was quite comforted and even became eagerly interested and derived great pleasure from watching the boy over the edge of her nest—though she always thought that the Eggs would be much cleverer and learn more quickly. But then she said indulgently that humans were always more clumsy and slow than Eggs and most of them never seemed really to learn to fly at all. You never met them in the air or on tree-tops.

How does the robin's mate's final comment, "humans were always more clumsy and slow than Eggs and most of them never seemed really to learn to fly at all. You never met them in the air or on tree-tops," contribute to the overall tone of the narrative?