Crossword Genius

Pulp eaten by bird, sticky thing (8)

Ross

I believe the answer is:

flypaper

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'bird sticky thing' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'pulp eaten by' is the wordplay.
'pulp' becomes 'pap' (both can mean worthless or trivial stuff).
'eaten' means one lot of letters goes inside another.
'by' becomes 'flyer' (I am not sure about this - if you are sure you should believe this answer much more).
'pap' placed within 'flyer' is 'FLYPAPER'.

Can you help me to learn more?

(Other definitions for flypaper that I've seen before include "Sticky stuff to trap insects" , "Killer" , "Sticky insect trap" , "for hanging being used for killing" , "should stick to the buzzer" .)

I've seen this clue in The Times.
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