The line is "Each must enter the nest made by the other imperfect birds",

and it's really about how these kind of scraggly, raggedy nests that are our lives are the sanctuary for other people to step into, and that if you want to see the divine, you really step into the absolute ordinary. 

When you're at your absolutely most lost and dejected ... where do you go? You go to the nests left by other imperfect birds, you find other people who've gone through it. You find the few people you can talk to about it.

from Writer's Digest May/June 2010
Anne Lamott
(Author is referring to the quote by Rumi)
Ribbon-tailed Astrapia, a Bird of Paradise