Tasman Sea island thrush explained

The Tasman Sea island thrush (Turdus poliocephalus) is an extinct forest bird in the thrush family that was formerly found on Lord Howe Island and Norfolk Island in the Pacific Ocean. It is part of the "island thrush" complex that has been split into 17 species based on a molecular phylogenetic study published in 2023. The two subspecies of the Tasman Sea island thrush became extinct in historical times.

Taxonomy

The Tasman Sea island thrush was formally described in 1801 by the English ornithologist John Latham based on a specimen that had been collected on Norfolk Island in the Pacific Ocean. He coined the binomial name Turdus poliocephalus,^{[1] [2]} where the specific epithet combines the Ancient Greek πολιος/polios meaning "grey" or "grizzled" with -κεφαλος/-kephalos meaning "-headed".^[3] The Tasman Sea island thrush, under the name "island thrush", formerly included around 50 subspecies and had a range that extended from the Philippines through the Greater Sundas, Wallacea, and New Guinea to Polynesia. The island thrush complex was split into 17 separate species based on morphological differences and a molecular phylogenetic study published in 2023.^{[4] [5] [6]}

Two subspecies are recognised, both of which are now extinct:^[5]

• † T. p. vinitinctus (Gould, 1855) – Lord Howe Island (east of Australia)
• † T. p. poliocephalus Latham, 1801 – Norfolk Island (east of Australia)

Conservation

The two subspecies have become extinct: T. p. vinitinctus from Lord Howe Island and the nominate race T. p. poliocephalus from Norfolk Island. T. p. poliocephalus was relatively common as recently as 1941, but by 1975 it had become extinct, due to introduced black rats, habitat loss and hybridization following colonisation by the closely related common blackbird.

References

• Collar, N. J. (2005) Family Turdidae (Thrushes) pp. 514–811 in: del Hoyo. J., Elliott, A., Sargatal, J., (eds), Handbook of the Birds of the World, Volume Ten, Cuckoo-shrikes to Thrushes,

Notes and References

1. Book: Latham, John . John Latham (ornithologist) . 1801 . Supplementum Indicis ornithologici, sive systematis ornithologiae . Latin . London . Leigh and Sotherby . xliv .
2. Book: Mayr . Ernst . Ernst Mayr . Paynter . Raymond A. Jr . 1964 . Check-List of Birds of the World . 10 . Museum of Comparative Zoology . Cambridge, Massachusetts . 198 .
3. Web site: Jobling . James A. . poliocephalus . The Key to Scientific Names . Cornell Lab of Ornithology . 25 October 2024 .
4. Reeve . A.H. . Gower . G. . Pujolar . J.M. . Smith . B.T. . Petersen . B. . Olsson . U. . Haryoko . T. . Koane . B. . Maiah . G. . Blom . M.P.K. . Ericson . P.G.P. . Irestedt . M. . Racimo . F. . Jønsson . K.A. . 2023 . Population genomics of the island thrush elucidates one of earth's great archipelagic radiations . Evolution Letters . 7 . 1 . 24-36 . 10.1093/evlett/qrac006 . free .
5. Web site: Gill . Frank . Frank Gill (ornithologist) . Donsker . David . Rasmussen . Pamela . Pamela C. Rasmussen . August 2024 . Thrushes . IOC World Bird List Version 14.2 . International Ornithologists' Union . 26 September 2024 .
6. Web site: Clements . J.F.. James Clements (ornithologist) . Rasmussen . P.C. . Pamela C. Rasmussen . Schulenberg . T.S. . Iliff . M.J. . Fredericks . T.A. . Gerbracht . J.A. . Lepage . D. . Spencer . A. . Billerman . S.M. . Sullivan . B.L. . Smith . M. . Wood . C.L. . 2024 . The eBird/Clements checklist of birds of the world: v2024 . 26 October 2024 .