Fish-eater laying egg by small quarry (6)
I believe the answer is:
osprey
'fish-eater' is the definition.
(I've seen this before)
'egg by small quarry' is the wordplay.
'egg' becomes 'o' (an 'o' resembles an egg).
'by' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'quarry' becomes 'prey' (synonyms).
'o'+'s'+'prey'='OSPREY'
'laying' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for osprey that I've seen before include "Spy roe (anag)" , "Large bird preying on fish in inland waters" , "Fish-eating hawk" , "Marine bird of prey" , "Fish eagle" .)