Wading bird that may be on reef? (4)
I believe the answer is:
knot
This could be a double definition.
'wading bird that may be' is the first definition.
'knot' can be an answer for 'wading bird' (knot is a kind of wading bird). I am unsure of the rest of the definition.
'reef?' is the second definition.
(I've seen this before)
'on' acts as a link.
Can you help me to learn more?
(Other definitions for knot that I've seen before include "Gnarl" , "Tie cord - lump in timber" , "It may be tied" , "Nautical measure" , "To secure < > bird" .)