Such pigeons are released from traps (4)
I believe the answer is:
clay
'such pigeons are' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for clay that I've seen before include "Court surface" , "Earthenware" , "Material used by potter" , "Potter's material" , "Type of soil used in ceramics" .)