Angry Birds Invitations Estimated Time: 10 mins. Yields: 1 What You Need Felt Angry Bird Stickers Angry Bird Invitation How-To Cut Felt Cut felt to match the eye brows and beak. Then glue them onto the invitation. Tip: use an exacto knife. Sticker to Envelope Add a sticker to seal the envelope. Testing step that doesn’t have an image. Copy should be left aligned.