Bonin Grosbeak

Bonin Grosbeak (Chaunoproctus ferreorostris) was a stout-billed finch known from Japan's Bonin Islands, generally reconstructed with brownish plumage and a large seed-crushing bill. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).

The species is extinct and cannot now be observed in the wild. Taxonomic studies place it near rosefinches, either within Carpodacus or in the separate genus Chaunoproctus. Consequently, its behaviour, feeding and breeding cannot be described from modern field observation; surviving museum specimens, historical records and later genetic analysis provide the available evidence for its appearance and relationships (Wikipedia, general species account).