I think I may have figured it out partly.
The 1984 New Zealand Aviary is listed as having a condition rating of 5 with a replacement cost of $320,759. [a rating scale of 1 to 5 basically runs from 1 being tip-top condition, 5 being unusable]
Further down, under "Assets created or significant renewal since 2007" is listed New Zealand Native Aviary with a date of 2008 and a condition rating of 1.
Both are given the reference WE7.
My supposition is that there was a smaller aviary on the same site (as you surmised earlier) which is the 1984 one, and it or its remains is contained within or next to the 1992 aviary (renovated in 2008). I'm not sure if that is the case but that's what makes most sense to me because the 1984 aviary must still be there in order to appear on the asset list.
The 1984 New Zealand Aviary is listed as having a condition rating of 5 with a replacement cost of $320,759. [a rating scale of 1 to 5 basically runs from 1 being tip-top condition, 5 being unusable]
Further down, under "Assets created or significant renewal since 2007" is listed New Zealand Native Aviary with a date of 2008 and a condition rating of 1.
Both are given the reference WE7.
My supposition is that there was a smaller aviary on the same site (as you surmised earlier) which is the 1984 one, and it or its remains is contained within or next to the 1992 aviary (renovated in 2008). I'm not sure if that is the case but that's what makes most sense to me because the 1984 aviary must still be there in order to appear on the asset list.