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
Four-letter word words of this length are upsetting to some, for religious or personal sensitivity reasons, such as: "" (UK), "", "", "", and "" (UK). Racist, ableist, and slurs pertaining to an individual's sexual orientation may also qualify, such as "" (in the UK not a racial slur, but short for Mongol, or someone with Down syndrome - previously called Mongolism), "", "", "", "", "" and "". Several "four-letter words" have multiple meanings (some even serving as given names), and usually only offend when used in their vulgar senses, for example: "", "", "" (UK) and "" (UK). A borderline