Old king takes gold back for some birds (7)

I believe the answer is:
heronry
'for some birds' is the definition.
I can't judge whether this defines the answer.
'old king takes gold back' is the wordplay.
'old king' becomes 'henry' (I've seen this before. I am not sure about the 'old' bit.).
'takes' is an insertion indicator.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'back' says the letters should be written backwards.
'or' reversed gives 'ro'.
'henry' going around 'ro' is 'HERONRY'.
Can you help me to learn more?
(Other definitions for heronry that I've seen before include "Place for waders" , "bird colony" , "lot of long-legged chicks here" , "where the waders are kept" , "colony with large bills" .)
