Being ignored is literally the Worst Thing for a birdie.

↓ Transcript
Boss Bird: "Dennis, your punishment for stealing DB's millet... everybirdie will ignore you...."
Boss Bird: "FOR TWO HOURS."
Dennis: "Nooooooooooooooooo"
Dennis: "Aaaaaaaaaaaaaaaaa!"
Boss Bird: "Wanna see my new bell?
White Bird: "Yes!"