Global Trends in Bird Species Survival

Since 1988, the overall status of bird species worldwide has consistently declined. Bird species face a steadily increasing risk of extinction in each of the major regions of the world, although the change is more rapid in some regions than others. In the Nearctic realm,^[1] which includes Canada, the status of birds is better than in other regions of the world, and is declining relatively slowly.

Red List Index of bird species survival by biogeographic realm,^[1] 1988–2008 

Note: The Red List Index (RLI) is currently available for birds, mammals, amphibians and corals, and is under development for other taxa, but the time series of data is longest and richest for birds. RLI values range from 1 (no species at risk of extinction in the near-term) down to zero (all species are extinct). The low sensitivity of the index is balanced by comprehensive geographic coverage and representation of bird species.
Source:  BirdLife International and the International Union for Conservation of Nature (IUCN) (2011). Data are current as of 17 September 2010. Terrestrial biogeographic realms from the World Wildlife Federation (WWF) (2001), global generalization from the United Nations Environmental Programme (UNEP).

The RLI measures the overall extinction risk for a set of species. Risk is assessed based on standardized criteria, using information and data from a variety of sources. The RLI reflects only the largest changes in extinction risk. Species that are declining slowly or that have depleted populations that are still large generally do not affect the index, and so changes in the index should be seen as biologically significant.

Declines in the status of birds are seen not only across realms, but also across all habitat types, including terrestrial, freshwater and marine ecosystems. Declines are also seen across most bird species groups, such as waterbirds, game birds, raptors, and parrots. Seabirds such as albatrosses and large petrels have experienced particularly rapid deterioration over the past two decades, largely due to the expansion of commercial longline fisheries. Habitat destruction, degradation and fragmentation, invasive species, pollution and climate change also threaten bird species worldwide.^[2]

Several Canadian species have undergone population changes that have resulted in changes in their RLI category of extinction risk during 1988-2008. Kirtland’s Warbler has improved in status, while Greater Prairie Chicken, Black-footed Albatross, Kittlitz’s Murrelet and Chimney Swift have all declined.^[3] Note that the IUCN RLI assesses the global status of species, which cannot be directly compared with status within particular countries.

Related indicators

• Changes in Wildlife Species Disappearance Risks 

Other information

• Birdlife International Datazone: factsheets for the world’s birds
• Birdlife International State of the World’s Birds: Indicators for our Changing World
• Butchart SHM et al. (2004) Measuring Global Trends in the Status of Biodiversity: Red List Indices for Birds.
• Butchart SHM et al. (2005) Using Red List Indices to Measure Progress Toward the 2010 Target and Beyond.
• Butchart SHM et al. (2007) Improvements to the Red List Index.
• The IUCN Red List of Threatened Species

---

[1] A biogeographic realm is a broad division of the earth’s surface that shares similar environmental conditions and evolutionary history, and contains a geographically distinct set of natural communities.

[2] BirdLife International (2008) State of the World’s Birds: Indicators for Our Changing World.

[3] BirdLife International and IUCN (2011), data are current as of 17 September 2010.