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Many bird species are close to extinction

Zheng Jianping/www.rarebirdsyearbook.com

Over 1,200 bird species are considered globally threatened, because they have small and declining populations or ranges. Of these, 189 are Critically Endangered and face an extremely high risk of extinction in the immediate future. Threatened birds are found throughout the world, but are concentrated in the tropics and especially in forests. Population declines may be quick and catastrophic, but even small increases in mortality can threaten the survival of some species.


Key messages and case studies

One in eight of the world's birds faces extinction
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A significant proportion of the world’s biodiversity now faces extinction. It is not yet possible to quantify exactly how many species are at risk, because we have not even named about 90% of all species on Earth, let alone assessed their status. However, a few groups of organisms are well known, and their threat status has been comprehensively assessed using the criteria of the IUCN Red List, developed over many years as a scientifically objective way of assessing extinction risk. BirdLife International is the official Red List Authority for birds, tasked with evaluating the status of the world's entire avifauna and keeping these data up-to-date. As of the 2011 update, 1,253 bird species (12.5% of the total, or one in eight) are globally threatened with extinction because of their small and declining populations or ranges. Of these, 189 species are Critically Endangered, meaning that they face an extremely high risk of extinction in the immediate future (One in eight of all bird species is threatened with global extinction, Most threatened birds have small populations, Most threatened birds are declining, some catastrophically, Most threatened birds have small ranges). At the regional level, BirdLife’s assessment of the conservation status of Europe’s birds in 2004, showed that 43% of the continent’s avifauna was in an unfavourable condition—a deterioration from 38% a decade before (Nearly half of Europe’s birds have an unfavourable conservation status).



Threatened species are found throughout the world
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Globally threatened birds can be found in virtually every country in the world (Threatened birds occur in nearly all countries and territories). While many are restricted to single countries, some range across large numbers of states—over eighty in the case of Egyptian Vulture. Threatened species are found on both the largest land-masses and on some of the smallest islands—the entire global population of the threatened Ascension Frigatebird breeds on Boatswainbird Islet, a 1 km2 flat-topped rock off Ascension Island in the Atlantic Ocean. Oceanic islands have disproportionately large numbers of threatened birds because their bird species are particularly susceptible to human influence (Many globally threatened birds are restricted to small islands). Among seabirds, there are particularly high densities of threatened species in the international waters of the southern oceans, notably around New Zealand (The southern oceans are particularly important for globally threatened seabirds).



Tropical countries and forests are particularly important
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Although threatened birds are found from polar regions to the equator, they are concentrated in the tropics, largely in forests (Threatened birds occur in all habitats, but the majority are found in forest). Regions such as the tropical Andes, the Atlantic Forest of Brazil and the archipelagos of South-East Asia particularly stand out, with Brazil and Indonesia the two countries in the world with the highest numbers of threatened birds (122 and 119 species respectively) (Some countries are particularly important for threatened birds).



Declines can be quick and catastrophic
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Population declines of threatened species are not always slow and gradual, in line with progressive habitat loss or exploitation—on occasions, they can be extremely rapid and dramatic. Such precipitous declines can affect even formerly abundant species (Asian vulture populations have declined precipitously in less than a decade, Titicaca Grebe is being driven rapidly towards extinction owing to the unregulated use of gill nets).



Even small increases in mortality can threaten the survival of species
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For slow-breeding species, even quite small increases in mortality among adults can lead to significant population declines (Many albatross species are in alarming slow decline). For these species, the underlying causes are likely to have been operating for a while by the time declines are detected, and, even if remedial action is taken immediately, recoveries may not be seen for many years.