- Sabine's Gull
- Sabota Lark
- Sacred Kingfisher
- Saddle-billed Stork
- Saffron-billed Sparrow
- Saffron-crowned Tanager
- Saffron-headed Parrot
- Saffron Finch
- Saker Falcon
- Salinas Monjita
- Salvadori's Teal
- Salvin's Albatross
- San Cristobal Mockingbird
- Sand Lark
- Sand Martin
- Sanderling
- Sandwich Tern
- Sandy Gallito
- Santa Marta Antpitta
- Santa Marta Blossomcrown
- Santa Marta Brushfinch
- Santa Marta Mountain Tanager
- Santa Marta Parakeet
- Santa Marta Warbler
- Sapayoa
- Sapphire-bellied Hummingbird
- Sapphire-throated Hummingbird
- Sardinian Warbler
- Sarus Crane
- Satanic Nightjar
- Satin Bowerbird
- Satin Flycatcher
- Savanna Hawk
- Savanna Nightjar
- Saxaul Sparrow
- Scale-throated Earthcreeper
- Scaled Dove
- Scaly-breasted Cupwing
- Scaly-breasted Hummingbird
- Scaly-feathered Weaver
- Scaly-headed Parrot
- Scaly-naped Amazon
- Scaly-naped Pigeon
- Scaly-throated Honeyguide
- Scaly Ground Roller
- Scaly Thrush
- Scarce Swift
- Scarlet-breasted Fruit Dove
- Scarlet-chested Sunbird
- Scarlet-fronted Parakeet
- Scarlet-headed Blackbird
- Scarlet-rumped Tanager
- Scarlet-thighed Dacnis
- Scarlet Flycatcher
- Scarlet Robin
- Scheepmaker's Crowned Pigeon
- Schlegel's Asity
- Scimitar-billed Woodcreeper
- Scintillant Hummingbird
- Sclater's Whistler
- Scrub Greenlet
- Scrub Honeyeater
- Scrub Tanager
- Scrubtit
- Secretarybird
- Sedge Warbler
- Semicollared Flycatcher
- Semipalmated Plover
- Semipalmated Sandpiper
- Senegal Lapwing
- Sentinel Rock Thrush
- Sepia-capped Flycatcher
- Sharp-billed Canastero
- Sharp-tailed Sandpiper
- Shikra
- Shining Bronze Cuckoo
- Shining Flycatcher
- Shining Honeycreeper
- Shining Sunbeam
- Shiny Cowbird
- Shoebill
- Short-billed Canastero
- Short-billed Miner
- Short-billed Minivet
- Short-billed Pigeon
- Short-billed Pipit
- Short-eared Owl
- Short-legged Ground Roller
- Short-tailed Grasswren
- Short-tailed Hawk
- Short-tailed Starling
- Short-tailed Swift
- Short-toed Snake Eagle
- Short-toed Treecreeper
- Short-winged Cisticola
- Shy Albatross
- Shy Heathwren
- Siberian Blue Robin
- Siberian Jay
- Siberian Rubythroat (beicki)
- Siberian Stonechat
- Sickle-billed Vanga
- Sickle-winged Chat
- Sierra Nevada Brushfinch
- Sikkim Treecreeper
- Silver-beaked Tanager
- Silver-breasted Broadbill
- Silver-throated Tanager
- Silver-tipped Imperial Pigeon
- Silver Gull
- Silver Gull (scopulinus)
- Silver Pheasant
- Silver Teal
- Silvereye
- Silvery Grebe
- Sind Sparrow
- Singing Honeyeater
- Singing Starling
- Slate-throated Whitestart
- Slaty-backed Chat-Tyrant
- Slaty-backed Flycatcher
- Slaty-backed Forktail
- Slaty-backed Nightingale-Thrush
- Slaty-breasted Rail
- Slaty-crowned Antpitta
- Slaty-tailed Trogon
- Slaty Brushfinch
- Slaty Flowerpiercer
- Slaty Robin
- Slaty Spinetail
- Slender-billed Crow
- Slender-billed Greenbul
- Slender-billed Gull
- Slender-billed Scimitar Babbler
- Slender-billed Starling
- Slender-billed Thornbill
- Slender-billed Weaver
- Small-billed Elaenia
- Small Ground Finch
- Small Minivet
- Small Niltava
- Small Pratincole
- Small Tree Finch
- Smew
- Smoke-colored Pewee
- Smoky Robin
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Partridge
- Snow Pigeon
- Snowy-bellied Hummingbird
- Snowy-crowned Robin-Chat
- Snowy-crowned Tern
- Snowy Egret
- Sociable Lapwing
- Social Flycatcher
- Solitary Sandpiper
- Somali Bulbul
- Somali Ostrich
- Somali Sparrow
- Somali Starling
- Sombre Kingfisher
- Sombre Pigeon
- Song Thrush
- Song Wren
- Sooty-capped Bush Tanager
- Sooty-headed Bulbul
- Sooty Chat
- Sooty Gull
- Sooty Oystercatcher
- Sooty Shearwater
- Sooty Tyrannulet
- Sora
- Souimanga Sunbird
- South African Cliff Swallow
- South African Shelduck
- South American Painted-snipe
- South American Tern
- South Island Oystercatcher
- South Island Robin
- South Island Saddleback
- South Island Takahe
- Southern Bald Ibis
- Southern Banded Snake Eagle
- Southern Beardless Tyrannulet
- Southern Bentbill
- Southern Black Flycatcher
- Southern Black Tit
- Southern Brown-throated Weaver
- Southern Double-collared Sunbird
- Southern Emu-wren
- Southern Fiscal
- Southern Giant Petrel
- Southern Grey-headed Sparrow
- Southern Lapwing
- Southern Martin
- Southern Masked Weaver
- Southern Mealy Amazon
- Southern Mountain Cacique
- Southern Nightingale-Wren
- Southern Pied Babbler
- Southern Pochard
- Southern Red-billed Hornbill
- Southern Red Bishop
- Southern Royal Albatross
- Southern Screamer
- Southern Scrub Flycatcher
- Southern Scrub Robin
- Southern Silvery Kingfisher
- Southern White-faced Owl
- Southern White-fringed Antwren
- Southern Whiteface
- Southern Yellow-billed Hornbill
- Spangle-cheeked Tanager
- Spangled Drongo
- Spanish Imperial Eagle
- Spanish Sparrow
- Sparkling Violetear
- Speckle-breasted Woodpecker
- Speckled Hummingbird
- Speckled Mourner
- Speckled Mousebird
- Speckled Pigeon
- Speckled Tinkerbird
- Speckled Warbler
- Spectacled Imperial Pigeon
- Spectacled Longbill
- Spectacled Tyrant
- Spectacled Weaver
- Spectacled Whitestart
- Spike-heeled Lark
- Spiny-cheeked Honeyeater
- Spix's Spinetail
- Splendid Fairywren
- Splendid Starling
- Spoon-billed Sandpiper
- Spot-billed Ground Tyrant
- Spot-billed Pelican
- Spot-breasted Woodpecker
- Spot-crowned Barbet
- Spot-crowned Euphonia
- Spot-crowned Woodcreeper
- Spot-flanked Barbet
- Spot-flanked Gallinule
- Spot-tailed Sparrowhawk
- Spot-throated Flameback
- Spot-winged Falconet
- Spot-winged Pigeon
- Spotless Starling
- Spotted Antbird
- Spotted Barbtail
- Spotted Dove
- Spotted Flycatcher
- Spotted Harrier
- Spotted Kestrel
- Spotted Laughingthrush
- Spotted Nutcracker
- Spotted Owlet
- Spotted Pardalote
- Spotted Rail
- Spotted Redshank
- Spotted Sandpiper
- Spotted Shag
- Spotted Thick-knee
- Spotted Whistling Duck
- Spotted Wood Kingfisher
- Spotted Woodcreeper
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Square-tailed Drongo-Cuckoo
- Square-tailed Kite
- Squirrel Cuckoo
- Standardwing
- Steely-vented Hummingbird
- Stejneger's Scoter
- Stella's Lorikeet
- Steller's Eider
- Stephan's Emerald Dove
- Steppe Eagle
- Stierling's Wren-Warbler
- Stilt Sandpiper
- Stitchbird
- Stock Dove
- Stolid Flycatcher
- Stout-billed Cinclodes
- Stout-billed Cuckooshrike
- Stout Cisticola
- Straight-billed Reedhaunter
- Straight-billed Woodcreeper
- Straneck's Tyrannulet
- Straw-necked Ibis
- Streak-breasted Scimitar Babbler
- Streak-breasted Treehunter
- Streak-breasted Woodpecker
- Streak-capped Spinetail
- Streak-capped Treehunter
- Streak-chested Antpitta
- Streak-eared Bulbul
- Streak-headed Antbird
- Streak-headed White-eye
- Streak-necked Flycatcher
- Streak-throated Barwing
- Streaked Flycatcher
- Streaked Saltator
- Streaked Shearwater
- Streaked Spiderhunter
- Streaked Tuftedcheek
- Streaked Xenops
- Striated Babbler
- Striated Bulbul
- Striated Fieldwren
- Striated Grassbird
- Striated Grasswren
- Striated Heron
- Striated Laughingthrush
- Striated Pardalote
- Striated Swallow
- Striated Thornbill
- Striolated Bunting
- Stripe-breasted Rhabdornis
- Stripe-breasted Tit
- Stripe-cheeked Woodpecker
- Stripe-crowned Spinetail
- Stripe-headed Rhabdornis
- Stripe-tailed Hummingbird
- Stripe-throated Bulbul
- Stripe-throated Jery
- Stripe-throated Wren
- Stripe-throated Yuhina
- Striped Honeyeater
- Striped Kingfisher
- Striped Owl
- Striped Treehunter
- Striped Woodpecker
- Strong-billed Honeyeater
- Strong-billed Woodcreeper
- Stubble Quail
- Stuhlmann's Starling
- Subdesert Brush Warbler
- Subdesert Mesite
- Subtropical Cacique
- Suiriri Flycatcher
- Sula Lorikeet
- Sulawesi Babbler
- Sulawesi Blue Flycatcher
- Sulawesi Cicadabird
- Sulawesi Drongo
- Sulawesi Dwarf Kingfisher
- Sulawesi Fantail
- Sulawesi Goshawk
- Sulawesi Hawk-Eagle
- Sulawesi Hornbill
- Sulawesi Leaf Warbler
- Sulawesi Lilac Kingfisher
- Sulawesi Myna
- Sulawesi Myzomela
- Sulawesi Scops Owl
- Sulawesi Serpent Eagle
- Sulphur-bearded Reedhaunter
- Sulphur-bellied Bulbul
- Sulphur-bellied Flycatcher
- Sulphur-bellied Tyrannulet
- Sulphur-bellied Warbler
- Sulphur-billed Nuthatch
- Sulphur-crested Cockatoo
- Sulphur-rumped Tanager
- Sulphur-vented Whistler
- Sultan's Cuckoo-Dove
- Sultan Tit
- Summer Tanager
- Sunbittern
- Sunda Pygmy Woodpecker
- Sunda Teal
- Sunda Zebra Finch
- Sungrebe
- Superb Fairywren
- Superb Fruit Dove
- Superb Lyrebird
- Superb Parrot
- Superciliaried Hemispingus
- Surfbird
- Surucua Trogon
- Swainson's Flycatcher
- Swainson's Hawk
- Swainson's Sparrow
- Swainson's Spurfowl
- Swainson's Thrush
- Swallow-tailed Gull
- Swallow-tailed Kite
- Swallow Tanager
- Swamp Flycatcher
- Swamp Harrier
- Swee Waxbill
- Swinhoe's Snipe
- Sword-billed Hummingbird
- Sykes's Lark
- Sykes's Nightjar
- Sykes's Warbler