The populations of over seventy-five percent of threatened birds are below 10,000 individuals, and nearly half are below 2,500 individuals. Some 58 species have tiny populations that may support no more than 50 individuals worldwide.
Over seventy-five percent (963 species) of threatened birds have populations of fewer than 10,000 individuals, while 42% (520 species) are below 2,500 individuals (see figure). In total, 58 species (5% of threatened birds) have tiny populations that possibly number fewer than 50 individuals. For example, there are 40–45 adult Tahiti Monarchs Pomarea nigra left on Tahiti, French Polynesia, and only 30–35 Puerto Rican Amazons Amazona vittata on Puerto Rico. For most species with small populations, their numbers are also believed to be declining. Only 280 threatened species (22%) have populations that are estimated to exceed 10,000 individuals. Most of these species qualify as threatened because their populations are undergoing rapid declines.
Related Case Studies in other sections
Compiled 2004, updated 2008, 2011
BirdLife International (2011) Most threatened birds have small populations. Presented as part of the BirdLife State of the world's birds website. Available from: http://www.birdlife.org/datazone/sowb/casestudy/107. Checked: 27/11/2015
|Key message: One in eight of the world's birds faces extinction|