From the Super Mario Wiki, the Mario encyclopedia
In The Super Mario Bros. Super Show! episode "Toad Warriors", King Koopa, attacking a Rebel Fort in Car Land, calls for the Thunder Birdo to use in the attack. Hearing King Koopa, Mouser rushes to get the Thunder Birdo, who he brings forward on a car.
Once in position, the Thunder Birdo fires a giant egg at the Rebel Fort, which explodes violently upon the building, heavily damaging it. After this first attack on the Rebel Fort, the Thunder Birdo continues blasting the building with more explosive eggs.
Later, after Mario and Princess Toadstool drive away from the semi-demolished Rebel Fort in a spaghetti sauce tanker truck, the Thunder Birdo, riding a car driven by Mouser, tries attacking them. Before the Thunder Birdo fires an egg at the tanker truck, Princess Toadstool, who is riding on the truck's top, throws a Bob-Omb bag into the Thunder Birdo's snout. The Thunder Birdo unwittingly swallows it on reflex, causing it to blow up.