Center for Biological Diversity
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Download a PDF of Appendix A — including photos, population graphs and species summaries.

Kierán Suckling, (520) 275-5960


Executive Summary

The Endangered Species Act is the world’s strongest law protecting animals and plants on the brink of extinction. It has saved more than 99 percent of species under its care from extinction. Less well studied, however, is how well it is moving imperiled species toward recovery, the Act's ultimate goal.

In this report, the most exhaustive and systematic analysis of its kind, we examine how well the Act is recovering species by determining the objective, long-term population trend of all 120 bird species listed as threatened or endangered since 1967. This study uses population counts from more than 1,800 wildlife surveys to determine 1) if bird populations increased, decreased or stabilized after being protected, 2) the magnitude of population change, 3) whether recovery rates are consistent with expectations of federal recovery plans, and 4) how endangered birds fared in comparison to more common birds.

Twenty-three birds had no Endangered Species Act population trend because they were last seen prior to being protected under the Act, were delisted for reasons unrelated to population trend, or were protected under the Act for fewer than 10 years. Our trend analyses are based on the remaining 97 species. On average our datasets spanned 83 percent of the time each species was protected by the Act, and thus represent the Act's long-term effect. See Appendix A: Population Trend Summary for All Threatened and Endangered Birds for photographs, population graphs and short narrative summaries of all 120 species.

We found that the Endangered Species Act has been extraordinarily successful in recovering imperiled birds:

• 85 percent of bird populations in the continental United States increased or stabilized while protected under the Act. • Pacific Island birds recovered less robustly, with 61 percent increased or stabilized since listing.

• The average population increase of all birds was 624 percent.

• Few species were expected to have recovered by 2015 because birds have been protected under the Act for 36 years on average, while their federal recovery plans expect 63 years will be necessary to fully recover them.

• Birds are recovering at the rate expected by their federal recovery plans.

• “Threatened” and “endangered” birds fared much better than unprotected birds, which on average declined 24 percent since 1974, indicating that it was the Endangered Species Act that improved species, not general environmental patterns. We recommend that several birds near extinction be prioritized for increased funding and immediate, intense conservation actions, and that recovery funding and effort be substantially increased in the Pacific Islands.