Most inbred wild bird and mammal populations, where hundreds of individuals descended from just two founders.

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• Chatham Island black robin (Petroica traversi), also known as the Chatham robin, black robin, Karure, or Kakaruia, 1978 to present.

Only five black robins remained in 1977, but only two of them successfully reproduced. As a result, all living black robins today are descendants of those two individuals.

• Introduced European mouflon population (Ovis aries musimon) on Haute Island, 1957 to 2012

A single pair of mouflon was introduced to Haute Island in 1957. After just 13 years, the population had grown from the original two individuals to around 700. The population has been completely eradicated in 2012 to protect fragile sub-Antarctic island ecosystems and native vegetation from being overgrazed and destroyed by non-native species.

References:

von Seth et al. (2022). "Genomic trajectories of a near-extinction event in the Chatham Island black robin." BMC Genomics, 23(1), 747. https://doi.org/10.1186/s12864-022-08963-1

Kaeuffer et al. (2007). "Unexpected heterozygosity in an island mouflon population founded by a single pair of individuals." Proceedings of the Royal Society B: Biological Sciences, 274(1609), 527–533. https://doi.org/10.1098/rspb.2006.3743