‘You are doubtless very big;
But all sorts of things and weather
Must be taken in together,
To make up a year
And a sphere.
And I think it no disgrace
To occupy my place.
If I'm not so large as you,
You are not so small as I,
And not half so spry.
I'll not deny you make
A very pretty squirrel track;
Talents differ; all is well and wisely put;
If I cannot carry forests on my back,
Neither can you crack a nut.'
Bun finally just says it; everything has a different role in life. While Bun isn’t large enough to carry forest, the mountain can’t crack a nut, which is vital as a squirrel. 
 Bun is what you’d call humble, but not in the traditional sense: Bun knows his place in the world, and his abilities in relationship to what surrounds him.