Tomorrow the Birds(1971)

Choujin Taikei

In the future, birds have taken over Earth and replaced human kind as the dominant species. With the assistance of bird-like aliens, the birds of Earth gained increased intelligence and began to attack humans. Now humans are treated as livestock by the birds who have moved on to create their own society with laws, currency, countries, and class systems. Ironically, the birds are following the same path as humans did.

Now, the meat-eating predatorial birds and the insect and grain eating birds have begun a war amongst each other that has no end in sight. As they fight, aliens begin to consider what species should replace the birds as the dominant species of Earth in this science fiction thriller.