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
Trumpeter (bird) Trumpeter (bird) The trumpeters are a family of birds restricted to the humid forests of the Amazon and Guiana Shield in South America. They are named for the trumpeting or cackling threat call of the males. The three species resemble chickens in size; they measure long and weigh . They are rotund birds with long necks and legs and curved bills and a hunched posture. Their heads are small, but their eyes are relatively large, making them look "good-natured". The plumage is soft, resembling fur or velvet on the head and neck. It is mostly black, with purple, green, or