The California Department of Fish and Wildlife writes (click here)
“Adult American bullfrogs have voracious appetites and will eat anything they can fit into their mouths, including invertebrates, birds, bats, rodents, frogs, newts, lizards, snakes, and turtles. Bullfrog tadpoles mainly eat algae, aquatic plant material, and invertebrates, but they will also eat the tadpoles of other frog species. As a result of these feeding behaviors, all life stages of bullfrogs prey upon and are able to out-compete native frogs and other aquatic species. Additionally, bullfrogs are a known carrier of chytrid fungus, which causes the potentially fatal skin disease in frogs called chytridiomycosis. Chytridomycosis is believed to be a leading cause of the decline of native amphibian populations all over the world and responsible for the extinction of over 100 species since the 1970s.”.
Apparently, the American bullfrog will, or will try to, eat anything that won’t eat it first. My extended family member, Eleanor, knew that bullfrogs had exterminated her singing chorus frogs, (genus Pseudacris, multiple species) and was not terribly surprised when she came upon this bullfrog attempting to swallow a pre-deceased adult bird, one that ultimately proved to be too large for consumption – but the frog came very close to swallowing something as large as itself!