They say take in bird food and be a winner! (7)
I believe the answer is:
succeed
'be a winner' is the definition.
(to succeed is to win)
I can't explain the rest of the clue.
(Other definitions for succeed that I've seen before include "Follow in order" , "accomplish aim" , "Make good" , "Come after or achieve a goal" , "Take the place previously occupied by - be a winner" .)