Boundary and skin
Built-in nest
housing school apartment building warehouse bridge
A cavity for birds or bats built into the wall, the eave or the facade. It can be a hollow brick with a small entrance, a built-in box or a slot under the eave.
What it solves
It gives back nesting and roosting places to species that lost the hollows of trees, cliffs and old buildings. Being part of the wall, it is unobtrusive, lasts as long as the building and the animal does not get inside.
Today
Place it high, away from windows and out of reach of cats, with an entrance just the right size for the species you want to invite. For bats, first seal the entrances to the ceiling or roof and offer the roost outside the inhabited space.
Common mistake
Leaving large gaps in eaves and ceilings that end up occupied by feral pigeons or by bat colonies inside the house, with dirt and smell.
Tomorrow
Locally made bricks and blocks can include standard nest pieces designed for the native birds and bats of each region. In schools, observing who lives in the wall can become a living lesson on the neighborhood’s wildlife.
Fact In a rural area of Costa Rica, about 16% of 129 houses studied had permanent bat colonies in the roof.
Where it comes from
- 1Persian dovecotes Isfahan, Iran, 17th century
A European traveler counted up to 3,000 pigeon towers around the city, built to collect the birds’ manure. - 2Starling pots Leiden and Amsterdam, Netherlands, 16th century
Clay jars with a hole were hung on facades as nests for starlings. - 3Colonial convent Old Havana, Cuba, study from 2012 and 2013
The holes left by scaffolding in the walls host nests, but almost half are occupied by the feral pigeon, an introduced species. - 4Natural environment law Scotland, United Kingdom, 2026
Parliament voted that new buildings must include swift bricks where reasonably practicable.
Appears in the routes
See also
Also in Boundary and skin
Diagrams and texts by LDB Arquitectura. They are shared under the CC BY 4.0 license, which allows them to be used and adapted with credit to the source.