Declaring a bird extinct: The median wait is 36 years after the last sighting
This article analyzes the significant time gap between the last sighting of a bird species and its official declaration of extinction. It highlights that the median wait time is 36 years, often due to rigorous scientific standards for confirming the absence of a species.
Why it matters
Understanding these delays is crucial for conservation efforts and accurately assessing the current biodiversity crisis.
A bird stops being seen. Then, eventually, somebody official says it is gone. The gap between those two moments is far longer than most people assume.
On this site there are thirteen species and subspecies for which both dates are documented: the last confirmed record, and the first formal declaration of extinction by a recognised authority. The median gap is 36 years . The mean is 47.5 . The shortest was three years — the dusky seaside sparrow , whose last individual died in a cage with a numbered band on its leg. The longest was 124 years : the Kauaʻi nukupuʻu , last collected in 1899 and not struck off the US endangered list until October 2023 .
Four more birds here have never been declared extinct at all, despite last records in 1935, 1944, 1956 and 1963.
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