When you have to clean up the mess an old person makes when moving to or from the place where the live during the winter.
Can also be used when cleaning up any other sort of mess a snowbird makes in their migration like a car accident, when they forget what they ordered at a restaurant and then bitch that you brought the wrong thing, or even if their camper catches on fire and burns down half the camp ground. All of this and much more is snowbird shit.
Erik knew he was going to have to clean up a lot of snowbird shit with this bastard. He was demanding all sorts of fees waved because he was too stupid to have his bills forwarded to his winter address.
The traffic on the highway was backed up for miles because some old bitch in a Lincoln is driving down the center line at 7 miles an hour and she just won't pull over. This is some serious snowbird shit right here and if I'm late for work I'm going to scream