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The status of the world's birds has deteriorated over the last 20 years

Rhinoceros Hornbill is one of several species which has deteriorated in status as a result of forest destruction in the Sundaic lowlands of Indonesia. © Yuliang/Dreamstime.com

The Red List Index for birds shows that there has been a steady and continuing deterioration in the status of the world’s birds between 1988 and 2008. The index is based on the movement of species between the categories of the IUCN Red List, with values relating to the proportion of species expected to survive in the near future, assuming no additional conservation action. Over these 20 years, 225 bird species have been uplisted to a higher category of threat because of genuine changes in status, compared to just 32 species downlisted.


The Red List Index for the world’s birds 1988–2008

Red List Index of species survival for all bird species (n = 9,798 non-Data Deficient species) showing the proportion of species expected to remain extant in the near future without additional conservation action. An RLI value of 1.0 equates to all species being categorised as Least Concern, and hence that none are expected to go extinct in the near future. An RLI value of zero indicates that all species have gone Extinct. Analysis of data held in BirdLife’s World Bird Database (2008).

The Red List Index (RLI) has been developed as an indicator of trends in the status of biodiversity. It is based on the movement of species through the categories of the IUCN Red List (Butchart et al. 2004, 2005, 2007). The RLI shows changes in the overall status (extinction risk) of sets of species, with RLI values relating to the proportion of species expected to remain extant in the near future without additional conservation action. 

The Red List Index for birds shows that there has been a steady and continuing deterioration in the status of the world’s birds between 1988 (when the first comprehensive global assessment was carried out by BirdLife International; Collar and Andrew 1988) and 2008 (BirdLife International 2008). The index is based on the number of species in each Red List category and the number that moved between categories as a result of genuine changes in status (i.e. excluding moves resulting from improved knowledge or taxonomic changes).

One strength of this index is that it illustrates the overall change in the status of birds in a clear and easily understood fashion, integrating the net effect of 225 species worsening in status (sufficient to be uplisted to a category of higher threat) and 32 species improving in status (sufficient to be downlisted to a category of lower threat). It is based on complete assessments of all the world’s birds (c.10,000 species) and hence is not biased to particular regions or better-known species.



Links

References

BirdLife International (2008) Threatened birds of the world 2008. CD-ROM. Cambridge: UK: BirdLife International.
 
Butchart, S. H. M., Stattersfield, A. J., Bennun, L. A., Shutes, S. M., Akçakaya, H. R., Baillie, J. E. M., Stuart, S. N., Hilton-Taylor, C. and Mace, G. M. (2004) Measuring global trends in the status of biodiversity: Red List Indices for birds. Public Lib. Sci. Biol. 2: 2294–2304.
 
Butchart, S. H. M., Stattersfield, A. J., Bennun, L. A., Akçakaya, H. R., Baillie, J. E. M., Stuart, S. N., Hilton-Taylor, C. and Mace, G. M. (2005) Using Red List Indices to measure progress towards the 2010 target and beyond. Phil. Trans. Roy. Soc. 1454: 255–268.
 
Butchart, S. H. M., Akçakaya, H. R., Chanson,J., Baillie, J. E. M., Collen, B., Quader, S., Turner, W. R., Amin, R., Stuart, S. N.,Hilton-Taylor, C. and Mace, G. M. (2007) Improvements to the Red List Index. Public Lib. Sci. One 2(1): e140. doi:10.1371/journal.pone.0000140
 
Collar, N. J. and Andrew, P. (1988) Birds to watch: the ICBP world checklist of threatened birds. Cambridge, UK: International Council for Bird Preservation and International Union for Conservation of Nature and Natural Resources.

Compiled 2004, updated 2008

Recommended Citation:
BirdLife International (2008) The status of the world's birds has deteriorated over the last 20 years. Presented as part of the BirdLife State of the world's birds website. Available from: http://birdlife.org/datazone/sowb/casestudy/72. Checked: 22/12/2014