Bird species with unusual or severe combinations of traits are most at risk of extinction, according to a recent study. The results are presented in the journal Functional Ecology of the British Ecological Society. According to a recent study by scientists at Imperial College London, the most striking birds on Earth are also the most endangered. The loss of these species and their distinctive ecological functions, such as seed dispersal, pollination and predation, can negatively impact ecosystem health. The study, which is the most thorough to date, examined the extinction risk and physical characteristics (such as wing length and beak shape) of 99 percent of all living bird species. The scientists found that there would be a noticeably greater reduction in physical (or morphological) diversity among birds in simulated scenarios where all endangered and near-threatened bird species went extinct than in scenarios where extinctions were random. The Christmas frigatebird (Fregata andrewsi), which breeds only on Christmas Island, and the bristle-thigh curlew (Numenius tahitiensis), which migrate annually from its breeding grounds in Alaska to South Pacific islands, are two bird species that are both morphologically distinctive and endangered.