GoKawiilStudy: birds wait median 36 years after last sighting before being declared extinct
An analysis of 13 bird species and subspecies with documented last-sighting and extinction-declaration dates finds a median gap of 36 years, and a mean of 47.5 years, between the two. The shortest gap was three years, for the dusky seaside sparrow; the longest was 124 years, for the Kauaʻi nukupuʻu, not delisted by the US government until October 2023. Four additional birds with last records between 1935 and 1963 have never been formally declared extinct.
GoKawiil's interpretation of the reporting above, not reported fact.
The delay stems from the IUCN's extinction standard, which requires 'no reasonable doubt' that the last individual has died — a negative claim that is inherently hard to prove given incomplete survey coverage. This suggests official extinction lists likely understate real losses for years or decades, which could affect conservation funding and priority-setting that depend on formal status changes.
- Median wait between last sighting and extinction declaration is 36 years, among 13 documented cases
- Kauaʻi nukupuʻu took 124 years to be delisted; dusky seaside sparrow took just 3
- Four birds with last records from 1935–1963 have never been formally declared extinct
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Published there as: “Declaring a bird extinct: The median wait is 36 years after the last sighting”
Read the original report → The summary and analysis above are GoKawiil's own, written from reporting by the source above. Facts and quotes belong to the original publisher.