Constantin Wilhelm Lambert Gloger theorises that dark pigments increase in races of animals living in warm and humid habitats in a work entitled Das Abändern der Vögel durch Einfluss des Klima's
ornithology | 1833 | Ornithology | 1833 territorial division of Spain | World Series of Birding | Slavery Abolition Act 1833 | Saint Helena Act 1833 | American Birding Association | 1833 Sumatra earthquake | The Ornithology of Australia | Stanisław Poniatowski (1754–1833) | Quakers and Moravians Act 1833 | Ornithology (composition) | One of the illustrations of ''Gamiani, or Two Nights of Excess'' published in Brussels in 1833. Illustration by Achille Devéria | Edmond (1833) | Chilean Constitution of 1833 | British Trust for Ornithology | Battle of Cape St. Vincent (1833) |