Birdseed is a food eaten and favored by birds, especially Big Bird, who not only likes birdseed, but often has snacks where birdseed is the main ingredient.
One of Big Bird's favorite snacks is Birdseed Milkshakes, which he often has at Hooper's Store. In Big Bird Gets Lost, he heads off to buy birdseed so he can make a birdseed cake for his nestwarming party. In A Muppet Family Christmas, he gives The Swedish Chef the gift of chocolate covered birdseed, which he made himself. In Episode 4086, Big Bird and Alan some birdseed cookies in preparation for a visit from Granny Bird. In Episode 3825, Big Bird has birdseed toast for breakfast.