A nest is a location in which haibane live between the time at which they hatch from their cocoon and the time at which their fate is decided (i.e. they attain their Day of Flight or become a failed haibane). Haibane nests seen in the series include Old Home and Abandoned Factory, but there may be more.
In agreement with the rule that haibane can only make use of things discarded by humans, haibane can only make a home in a place that has been abandoned after prolonged use. Cocoons materialize within a nest by means unknown. There, it is discovered by the other haibane living there, who care for and watch over the area until it hatches.
Within a nest, it is up to the haibane to work together and learn from one another until they pass or fail whatever trial they exist to face. Many appear to be unaware of the trial process as a formality, instead appearing to simply understand that there is a time at which haibane come into the world, and a time at which they achieve they leave it.
Most haibane take jobs in town and do their part to help around the nest, but some, like Reki, may work in the nest full time. Because the population of a nest is ever-changing, a sort of de facto leadership responsibility falls on whatever haibane has lived there the longest.
Symbolism and Interpretations
The rule that haibane are only to live in and make use of what has been left behind by humans seems to exist in order to prevent haibane from being distracted from their trails - and the nest would be no exception. They are much less likely to be diverted if they are unable to become too attached to any objects, desires, or people, and yet they are much more likely to overcome their trials and understand the purpose of their existence if they are not alone.
Within a nest, a haibane will find shelter, food, and social support, but will not become tied down to a particular location or group, as the group is always changing and the home not only belongs to no one, but has the label of being abandoned and discarded.
Unanswered Questions and Theories
Why do cocoons only form in nests?
- How cocoons materialize in the world is a mystery, but an even bigger mystery is how they know where to form. Does a nest originally come together around a place that cocoons materialize, or to cocoons begin to materialize within a nest after it has been chosen by a founding group?
- It is possible that the Haibane Renmei are somehow able to designate the area as a nest for future coccoons. If the Renmei are the ones who place the named plaques within the Walls of Glie for light flakes to collect on, it is possible that they also know how to bestow such a designation on an area.
- Another possibility is that the unseen force that turned them into haibane to begin with chooses where to place them. The series implies that haibane, having lived past lives and being given trials, are being allowed a second chance at something - but at what, and by whom? Perhaps this entity places the cocoon.