- Stripe-throated Tit Babbler
- Stripe-throated Wren
- Stripe-throated Yuhina
- Striped Babbler
- Striped Bowerbird
- Striped Buttonquail
- Striped Crake
- Striped Crested Cuckoo
- Striped Cuckoo
- Striped Flowerpecker
- Striped Flufftail
- Striped Honeyeater
- Striped Kingfisher
- Striped Laughing-thrush
- Striped Laughingthrush
- Striped Manakin
- Striped Owl
- Striped Pipit
- Striped Prinia
- Striped Sparrow
- Striped Starling
- Striped Tiger
- Striped Tit-Babbler
- Striped Tit Babbler
- Striped Tree-Babbler
- Striped Treehunter
- Striped Woodcreeper
- Striped Woodhaunter
- Striped Woodpecker
- Striped Wren-Babbler
- Striped Wren Babbler
- Strix
- Strix albitarsis
- Strix albitarsus
- Strix aluco
- Strix bartelsi
- Strix butleri
- Strix chacoensis
- Strix davidi
- Strix fulvescens
- Strix hadorami
- Strix huhula
- Strix hylophila
- Strix leptogrammica
- Strix mauritanica
- Strix nebulosa
- Strix newarensis
- Strix nigrolineata
- Strix nivicola
- Strix nivicolum
- Strix occidentalis
- Strix occidentalis caurina
- Strix occidentalis lucida
- Strix ocellata
- Strix omanensis
- Strix rufipes
- Strix sartorii
- Strix seloputo
- Strix uralensis
- Strix uralensis japonica
- Strix varia
- Strix virgata
- Strix virgata centralis
- Strix woodfordii
- Strix woodfordii nuchalis
- Strong-billed Honeyeater
- Strong-billed Woodcreeper
- Strong Billed Woodcreeper
- Strophocincla
- Strophocincla cachinnans
- Strophocincla fairbanki
- Strophocincla imbricata
- Strophocincla lineata
- Strophocincla virgata
- Strumpshaw Fen
- Strumpshaw Fen RSPB Reserve
- Struthidea
- Struthidea cinerea
- Struthideidae
- Struthio
- Struthio camelus
- Struthio molybdophanes
- Struthionidae
- Struthioniformes
- Stub-tailed Antbird
- Stub-tailed Spadebill
- Stubble Quail
- Stubs
- Studen Kladenetz
- Studen Kladenetz Bulgaria
- Stuhlmann's Double-collared Sunbird
- Stuhlmann's Starling
- Stuhlmann's Sunbird
- Sturnella
- Sturnella Loyca
- Sturnella bellicosa
- Sturnella defilippii
- Sturnella lilianae
- Sturnella loyca
- Sturnella loyca falklandica
- Sturnella loyca loyca
- Sturnella magna
- Sturnella militaris
- Sturnella neglecta
- Sturnella superciliaris
- Sturnia
- Sturnia Pagodarum
- Sturnia albofrontata
- Sturnia blythii
- Sturnia erythropygia
- Sturnia malabarica
- Sturnia pagodarum
- Sturnia philippensis
- Sturnia sinensis
- Sturnia sturnina
- Sturnidae
- Sturnornis
- Sturnornis albofrontatus
- Sturnus
- Sturnus albofrontatus
- Sturnus blythii
- Sturnus burmannicus
- Sturnus cineraceus
- Sturnus contra
- Sturnus erythropygius
- Sturnus malabaricus
- Sturnus melanopterus
- Sturnus nigricollis
- Sturnus pagodarum
- Sturnus philippensis
- Sturnus roseus
- Sturnus senex
- Sturnus sericeus
- Sturnus sinensis
- Sturnus sturninus
- Sturnus unicolor
- Sturnus vulgaris
- Styan's Bulbul
- Styan's Grasshopper-Warbler
- Styan's Grasshopper Warbler
- Styan's Warbler
- Stygian Owl
- Stymphalornis
- Stymphalornis acutirostris
- Subalpine Robin
- Subalpine Warbler
- Subantarctic Shearwater
- Subantarctic Skua
- Subantarctic Snipe
- Subdesert Brush-Warbler
- Subdesert Brush Warbler
- Subdesert Mesite
- Sublegatus
- Sublegatus arenarum
- Sublegatus modestus
- Sublegatus obscurior
- Subtropical Cacique
- Subtropical Doradito
- Subtropical Pygmy-Owl
- Subtropical Pygmy Owl
- Such's Antthrush
- Sucre Antpitta
- Sucunduri Flycatcher
- Sudan
- Sudan Babbler
- Sudan Brown Babbler
- Sudan Golden Sparrow
- Sudan Petronia
- Sudan Rock-Sparrow
- Sudan Rock Sparrow
- Sudest Butcherbird
- Sudest Honeyeater
- Sudest Meliphaga
- Suffolk
- Sugomel niger
- Sugomel nigrum
- Suiriri
- Suiriri Flycatcher
- Suiriri affinis
- Suiriri islerorum
- Suiriri suiriri
- Sukatschev's Laughingthrush
- Sula
- Sula Barn Owl
- Sula Cicadabird
- Sula Cuckoo-Dove
- Sula Cuckoo-shrike
- Sula Cuckoo Dove
- Sula Cuckooshrike
- Sula Dwarf-Kingfisher
- Sula Dwarf Kingfisher
- Sula Fruit-Dove
- Sula Fruit Dove
- Sula Golden-Bulbul
- Sula Golden Bulbul
- Sula Hanging-Parrot
- Sula Hanging Parrot
- Sula Island Masked-Owl
- Sula Island Masked Owl
- Sula Islands Cicadabird
- Sula Jungle-Flycatcher
- Sula Jungle Flycatcher
- Sula King Myna
- Sula Lorikeet
- Sula Magpie
- Sula Megapode
- Sula Myna
- Sula Pitta
- Sula Scops-Owl
- Sula Scops Owl
- Sula Scrubfowl
- Sula Starling
- Sula abbotti
- Sula dactylatra
- Sula dactylatra personata
- Sula granti
- Sula leucogaster
- Sula leucogaster plotus
- Sula nebouxii
- Sula nebouxii excisa
- Sula piscator
- Sula sula
- Sula sula rubripes
- Sula sula websteri
- Sula variegata
- Sulawesi
- Sulawesi Babbler
- Sulawesi Blue-Flycatcher
- Sulawesi Blue Flycatcher
- Sulawesi Brown Flycatcher
- Sulawesi Bush Warbler
- Sulawesi Cicadabird
- Sulawesi Crested Goshawk
- Sulawesi Crested Myna
- Sulawesi Cuckoo
- Sulawesi Cuckoo-shrike
- Sulawesi Cuckooshrike
- Sulawesi Drongo
- Sulawesi Dwarf-Hornbill
- Sulawesi Dwarf-Kingfisher
- Sulawesi Dwarf Kingfisher
- Sulawesi Fantail
- Sulawesi Goshawk
- Sulawesi Ground-Dove
- Sulawesi Ground Dove
- Sulawesi Hanging-Parrot
- Sulawesi Hanging Parrot
- Sulawesi Hawk-Cuckoo
- Sulawesi Hawk-Eagle
- Sulawesi Hawk Cuckoo
- Sulawesi Hawk Eagle
- Sulawesi Honey-buzzard
- Sulawesi Honey Buzzard
- Sulawesi Honeyeater
- Sulawesi Hornbill
- Sulawesi King Starling
- Sulawesi Kingfisher
- Sulawesi Leaf-Warbler
- Sulawesi Leaf Warbler
- Sulawesi Lilac Kingfisher
- Sulawesi Magpie
- Sulawesi Malia
- Sulawesi Masked-Owl
- Sulawesi Masked Owl
- Sulawesi Mountain Whistler
- Sulawesi Myna
- Sulawesi Myzomela
- Sulawesi Nightjar
- Sulawesi Owl
- Sulawesi Pied Imperial Pigeon
- Sulawesi Pitta
- Sulawesi Pygmy Woodpecker
- Sulawesi Scops-Owl
- Sulawesi Scops Owl
- Sulawesi Serpent-Eagle
- Sulawesi Serpent Eagle
- Sulawesi Streaked Flycatcher
- Sulawesi Swiftlet
- Sulawesi Tarictic Hornbill
- Sulawesi Thrush
- Sulawesi Waterhen
- Sulawesi Whistler
- Sulawesi White-eye
- Sulawesi Woodcock
- Sulawesi Woodpecker
- Sulawesi Wrinkled Hornbill
- Sulidae
- Suliformes
- Sulphur-bearded Reedhaunter
- Sulphur-bearded Spinetail
- Sulphur-bellied Bulbul
- Sulphur-bellied Flycatcher
- Sulphur-bellied Neopelma
- Sulphur-bellied Tyrannulet
- Sulphur-bellied Tyrant-Manakin
- Sulphur-bellied Tyrant Manakin
- Sulphur-bellied Warbler
- Sulphur-bellied Whistler
- Sulphur-billed Nuthatch
- Sulphur-breasted Bush-Shrike
- Sulphur-breasted Bushshrike
- Sulphur-breasted Leaf Warbler
- Sulphur-breasted Myzomela
- Sulphur-breasted Parakeet
- Sulphur-breasted Toucan
- Sulphur-breasted Warbler
- Sulphur-crested Cockatoo
- Sulphur-rumped Flycatcher
- Sulphur-rumped Myiobius
- Sulphur-rumped Tanager
- Sulphur-throated Finch
- Sulphur-throated Spinetail
- Sulphur-vented Whistler
- Sulphur-winged Parakeet
- Sulphur White-eye
- Sulphury Flycatcher
- Sultan's Cuckoo-Dove
- Sultan's Cuckoo Dove
- Sultan Tit
- Sultanpur Bird Sanctuary
- Sultanpur Jheel
- Sultanpur National Park
- Sulu Bleeding-heart
- Sulu Boobook
- Sulu Hawk-Owl
- Sulu Hawk Owl
- Sulu Hornbill
- Sulu Pitta
- Sulu Pygmy Woodpecker
- Sulu Woodpecker
- Sumatra
- Sumatran Babbler
- Sumatran Bulbul
- Sumatran Cochoa
- Sumatran Crested Jay
- Sumatran Drongo
- Sumatran Flowerpecker
- Sumatran Frogmouth
- Sumatran Green-Pigeon
- Sumatran Green Pigeon
- Sumatran Ground-Cuckoo
- Sumatran Ground Cuckoo
- Sumatran Hill-Partridge
- Sumatran Hill Partridge
- Sumatran Large Wren-Babbler