Bird flapping in time cut short (7)
I believe the answer is:
abridge
'cut short' is the definition.
(to abridge something is to make it shorter)
'bird flapping in time' is the wordplay.
'flapping' indicates anagramming the letters (flap can mean to move or fly around).
'in' means one lot of letters goes inside another.
'time' becomes 'age' (an age is a period of time).
'bird' anagrammed gives 'brid'.
'brid' inserted inside 'age' is 'ABRIDGE'.
(Other definitions for abridge that I've seen before include "Big read (anag) - shorten text" , "Abbreviate, contract" , "Make shorter, book say" , "Condense, summarise" , "Crop" .)