Soft things. Tiny things. Delicate things.
When handed one of the above the natural reaction is to cradle it gently in your hand. You want to be kind. Avoid doing damage.
Consider a bird nest for a moment. They are designed to hold and protect soft, tiny, delicate birds. And while they vary in size, location, and building material, all of the parents are following instinct to do the best for the next generation.
The glass artist has captured the spirit of the nest in the shape of the glass as well as in the careful position in the tree.