Population trends of globally threatened birds

Analysis of data held in BirdLife’s World Bird Database (2017)

Most threatened birds have declining populations: in total 1197 species (81.9% of threatened species) are declining, and 474 (33%) qualify as threatened because the declines exceed 30% in 10 years or three generations (whichever is longer). Thirty-six species are estimated or inferred to have declines that exceed 80% in 10 years or three generations. For example, since the 1960s the population of the formerly common Mariana Crow Corvus kubaryi has become extinct on Guam despite a reintroduction effort (L. Barnhart Duenas in litt. 2013, 2014). On Rota it was thought to be stable, estimated at 1,318 Mariana Crows in 1982, but has since declined to c.50 confirmed breeding pairs in 2016 (Faegre et al. 2016). Similarly, surveys on the breeding grounds of Spoon-billed Sandpiper Calidris pygmaea show that the species has declined extremely rapidly from an estimated 2,000–2,800 pairs in the 1970s to an optimistic estimation of 120 – 200 pairs in 2010 (Zöckler et al. 2010a). Only 152 threatened species (10.8% of those with estimates) have stable populations, and just 53 (3.8%) have increasing populations, almost all in response to conservation efforts (e.g. St Lucia Parrot Amazona versicolor).