"Few other animals have attained to the skill of weaving displayed by birds," wrote W.P. Pycraft in the Nest entry of the 1956 Encyclopedia Britannica.

I hadn't thought of it like that.

Why do birds' nests hang together and contain? Birds don't nail, don't glue, don't put sticks and twigs wherever.

They make a unity that works for them by weaving. Put it here.