Flightless bird requirement for flightlessness. The kiwi does not exhibit gigantism, along with tinamous, even though they coexisted with the moa and rhea that both exhibit gigantism. This could be the result of different ancestral flighted birds arrival or because of competitive exclusion. The first flightless bird to arrive in each environment utilized the large flightless herbivore or omnivore niche, forcing the later arrivals to remain smaller. In environments where flightless birds are not present, it is possible that after the K/T Boundary there were no niches for them to fill. They were pushed out by other herbivorous mammals. New Zealand had
Flightless cormorant Flightless cormorant The flightless cormorant ("Phalacrocorax harrisi"), also known as the Galapagos cormorant, is a cormorant native to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only cormorant that has lost the ability to fly. Once it was placed in its own genus, "Nannopterum" or "Compsohalieus", although current taxonomy places it in the genus with most of the other cormorants, "Phalacrocorax". Like all cormorants, this bird has webbed feet and powerful legs that propel it through ocean waters as it seeks its prey of fish, eels, small octopuses,