This work is specific to the architecture of the tropical arc glasshouse and engaged in an aural call and response with a large 'pipe' suspended some distance away. The speaker is housed in a well-used Australian utensil, a Billy, which faces and speaks to a Wok. The Wok acts as a parabolic reflector projecting sound toward the visitor on the upper level of the building.
The sounds are melodic cooees*, in response to sounds coming from "The Pipe" (not pictured here).

* a shout used in the Australian Outback which can carry over a considerable distance.