These changes, which gave birds greater facility for flight, made them more effective predators. It’s not difficult to imagine that they feasted on giant insects.
That’s one theory, at least. Another holds that rather than eat giant insects, prehistoric birds simply out competed them. Both birds and giant insects ate smaller insects that existed alongside their super-sized cousins. Evolution may have enabled birds not only to dine on giant insects but also to consume smaller insects and deplete their competitors’ food source.