Birds

Terpsiphone bourbonnensis

Terpsiphone bourbonnensis, the Mascarene Paradise Flycatcher (Oiseau la Vierge, Tchitrec des Mascareignes), is a monarch flycatcher endemic to Réunion and Mauritius, IUCN Least Concern, with about 49,500 birds on Réunion and only 200-300 pairs on Mauritius.

Tesia

Tesia, genus of tiny, nearly tail-less cettiid warblers (Cettiidae) of Himalayan and Southeast Asian undergrowth; four species including Grey-bellied Tesia (type) and Javan Tesia; eight tail feathers.

Tetrao

Tetrao (capercaillies), genus of large Palearctic forest grouse in Phasianidae with two species, western capercaillie T. urogallus and black-billed capercaillie T. urogalloides; both Least Concern but decreasing.

Tetrax

Tetrax, the little bustard (Tetrax tetrax), sole species of its bustard genus; a Near Threatened Palearctic steppe bird with western (Iberia) and eastern (Russia, Kazakhstan) populations, lekking males, and strong agricultural-intensification-driven declines.

Thalassarche

Thalassarche (mollymawks) is a genus of Southern Hemisphere albatrosses in Diomedeidae, erected by Reichenbach in 1853 and revived after the 1996 cytochrome-b revision, comprising about ten species including Black-browed and Grey-headed albatrosses.

Thalasseus

Thalasseus (Boie, 1822) is a genus of seven crested terns in Laridae, including Royal, Sandwich, and Chinese crested terns; plunge-diving seabirds whose black-crested head arose 4.2-7.2 million years ago.

Thamnophilidae

Thamnophilidae, the typical antbirds (antbirds, antshrikes, antwrens, antvireos), is a monophyletic South and Central American passerine family of about 239 species in 63 genera, known for army-ant-following behavior that evolved toward obligate dependence with no reversals.

Thamnophilus

Thamnophilus (typical antshrikes) is a Vieillot 1816 genus of Neotropical antbirds, family Thamnophilidae, type species T. doliatus; about 25-30 insectivorous, sexually dichromatic species across South American lowlands, Andes, and tepuis.

Thraupidae

Thraupidae (tanagers), family Cabanis 1847 of American passerine birds in Emberizoidea; about 4% of bird species, 13 subfamilies, includes Darwin's finches; redefined by molecular phylogenetics.

Threskiornis

Threskiornis is a genus of six large wading ibis species across Africa, Asia, and Australia, established by George Robert Gray in 1842; the sacred ibis was venerated in ancient Egypt.

Thrush (bird)

Thrush (bird): the Turdidae, a family of over 300 songbird species including true thrushes (Turdus), chats, and bluebirds, found on all continents except Australia and Antarctica; omnivorous ground foragers, mostly monogamous, with several declining species such as the Vulnerable Grey-sided Thrush.

Thryothorus

Thryothorus is a genus of wrens established by Vieillot in 1816; once holding 27 species, it was split by molecular studies and now contains only the Carolina Wren.

Tinamus

Tinamus (Hermann, 1783) is a genus of five large forest tinamous (guttatus, major, osgoodi, solitarius, tao) in Tinaminae, Neotropical palaeognath birds; 2025 taxonomy reassigns Crypturellus species to Tinamus.

Tinamus solitarius

Tinamus solitarius, the solitary tinamou or macuco, is a large paleognath ground bird endemic to the Atlantic Forest of eastern Brazil, Paraguay, and northeast Argentina; IUCN Near Threatened, population 50,000-200,000 mature individuals and declining from hunting and habitat loss.

Tit (bird)

Paridae, the true tits (tits, chickadees, titmice), is a passerine bird family of 62-63 small arboreal species across Eurasia, Africa, and North America, absent from Australia, nesting in tree holes and hoarding food in winter.

Toco toucan

Toco toucan (Ramphastos toco), largest toucan of central and eastern South America; huge hollow yellow-orange bill acts as a controllable thermal radiator; Least Concern, CITES Appendix II.

Todus

Todus (todies) is the sole living genus of the Caribbean family Todidae, order Coraciiformes: five tiny green, red-throated, burrow-nesting insectivores endemic to the Greater Antilles, none globally threatened.

Torosaurus

Torosaurus ("bull lizard") is a large Late Cretaceous ceratopsian dinosaur, 7.5 m long, from Canada and the USA, named by Marsh in 1891; debated as possibly an aged Triceratops but now generally considered valid.

Toucan

Toucan: Neotropical birds of Ramphastidae (Piciformes), about 37-50 species, known for oversized bills used for fruit, heat radiation, and nest raiding; threatened by Amazon deforestation and pet trade.

Touit

Touit (forest parrotlets), genus of eight small green Neotropical parrots in Psittacidae, type species Psittacus huetii; name conserved over Pyrrhulopsis by ICZN Opinion 2383; includes Brown-backed and Golden-tailed Parrotlets, both declining in Brazil's Atlantic Forest.

Toxostoma

Toxostoma (American thrashers), Wagler 1831, a Mimidae genus of 10 long-billed arid-land songbirds of the southwestern US and Mexico, from the common Brown Thrasher to the possibly extinct Cozumel Thrasher.

Tragopan

Tragopan, horned pheasants, genus of five Himalayan pheasant species (melanocephalus, satyra, blythii, temminckii, caboti) in Phasianidae; males display inflatable horns and lappet; Western Tragopan is Vulnerable with 3,200-9,500 mature individuals.

Traversia

Traversia is a monotypic New Zealand wren genus (Acanthisittidae) for the extinct, flightless Lyall's wren, Traversia lyalli Rothschild, 1894, last recorded on Stephens Island (Takapourewa) after feral cats became established there in 1894.

Treron

Treron (green pigeons), genus of 29 arboreal fruit-eating pigeon species in Columbidae across Asia and Africa; green plumage from dietary carotenoids, fig specialists, now placed in tribe Treronini within Raphinae.

Trichoglossus

Trichoglossus (Island Lories) is a genus of brush-tongued lorikeet parrots in tribe Loriini, Australasian nectar and pollen feeders including the rainbow lorikeet T. haematodus, expanded by 2024 AviList mergers of Saudareos and Eos.

Tringa

Tringa is a genus of wading birds in the sandpiper family Scolopacidae, established by Linnaeus in 1758 and containing the shanks, tattlers, yellowlegs, and the Willet.

Trochilus

Trochilus is a genus of hummingbirds established by Linnaeus in 1758, now containing only the two Jamaican streamertails, which differ chiefly in bill color: red in the Red-billed Streamertail and black in the Black-billed Streamertail.

Troglodytes

Troglodytes (Vieillot, 1809) is a genus of wrens in Troglodytidae, including the House Wren and Eurasian wren; molecular phylogenies show it is paraphyletic, with northern species moved to Nannus.

Trogon

Trogon (genus, Brisson 1760) is the largest Neotropical trogon genus, family Trogonidae, order Trogoniformes, with a unique heterodactyl foot; recent 2023-2025 splits raised its species count and renamed several English names.