- Sabine's Gull
- Saffron-billed Sparrow
- Saffron Finch
- Saffron Toucanet
- Sakalava Weaver
- Saker Falcon
- Salinas Monjita
- Saltmarsh Sparrow
- Salvadori's Teal
- Sandhill Crane
- Sapphire-vented Puffleg
- Satin Flycatcher
- Saunders's Gull
- Savanna Hawk
- Savannah Sparrow
- Say's Phoebe
- Sayaca Tanager
- Scale-crested Pygmy Tyrant
- Scale-throated Earthcreeper
- Scaled Antbird
- Scaled Dove
- Scaled Piculet
- Scalloped Woodcreeper
- Scaly-breasted Bulbul
- Scaly-breasted Cupwing
- Scaly-breasted Thrasher
- Scaly-crowned Babbler
- Scaly-headed Parrot
- Scaly-naped Pigeon
- Scaly-sided Merganser
- Scaly Thrush
- Scarlet-backed Woodpecker
- Scarlet-bellied Mountain Tanager
- Scarlet-breasted Fruiteater
- Scarlet-headed Blackbird
- Scarlet-rumped Tanager
- Scarlet-rumped Trogon
- Scarlet Flycatcher
- Scarlet Ibis
- Scarlet Macaw
- Scarlet Minivet
- Scarlet Tanager
- Scheepmaker's Crowned Pigeon
- Scimitar-billed Woodcreeper
- Sclater's Myzomela
- Sclater's Tyrannulet
- Scott's Oriole
- Screaming Piha
- Scrub Blackbird
- Scrub Euphonia
- Semipalmated Plover
- Semipalmated Sandpiper
- Sepia-capped Flycatcher
- Sharp-beaked Ground Finch
- Sharp-billed Canastero
- Sharp-shinned Hawk
- Sharp-tailed Streamcreeper
- Sharpbill
- Shear-tailed Grey Tyrant
- Shikra
- Shining Flycatcher
- Shining Sunbeam
- Shiny Cowbird
- Short-billed Dowitcher
- Short-billed Pigeon
- Short-billed Pipit
- Short-crested Flycatcher
- Short-tailed Hawk
- Short-tailed Swift
- Shrike-like Tanager
- Siberian Accentor
- Siberian Blue Robin
- Siberian Stonechat
- Siberian Thrush
- Sichuan Tit
- Sick's Swift
- Sickle-winged Guan
- Silver-beaked Tanager
- Silver-breasted Broadbill
- Silver-eared Laughingthrush
- Silver-eared Mesia
- Silver-throated Tanager
- Silver Teal
- Silvery Grebe
- Sinaloa Crow
- Slate-colored Fox Sparrow
- Slate-throated Whitestart
- Slaty-backed Chat-Tyrant
- Slaty-backed Flycatcher
- Slaty-backed Forktail
- Slaty-backed Gull
- Slaty-backed Nightingale-Thrush
- Slaty-breasted Rail
- Slaty-breasted Wood Rail
- Slaty-capped Shrike-Vireo
- Slaty-tailed Trogon
- Slaty Becard
- Slaty Brushfinch
- Slaty Elaenia
- Slaty Flowerpiercer
- Slaty Spinetail
- Slaty Vireo
- Slender-billed Finch
- Slender-footed Tyrannulet
- Small-billed Elaenia
- Small Ground Finch
- Small Tree Finch
- Smith's Longspur
- Smoke-colored Pewee
- Smoky-brown Woodpecker
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Goose
- Snowy-crowned Tern
- Snowy Cotinga
- Snowy Egret
- Snowy Plover
- Snowy Sheathbill
- Social Flycatcher
- Solitary Cacique
- Solitary Sandpiper
- Solitary Snipe
- Solitary Tinamou
- Song Sparrow
- Sooretama Slaty Antshrike
- Sooty-capped Babbler
- Sooty-capped Bush Tanager
- Sooty-faced Finch
- Sooty-fronted Spinetail
- Sooty-headed Bulbul
- Sooty-headed Tyrannulet
- Sooty Fox Sparrow
- Sooty Thrush
- Sooty Tyrannulet
- Sora
- South American Painted-snipe
- South American Snipe
- South American Tern
- South Polar Skua
- Southern Beardless Tyrannulet
- Southern Bristle Tyrant
- Southern Chestnut-tailed Antbird
- Southern Crested Caracara
- Southern Giant Petrel
- Southern Lapwing
- Southern Martin
- Southern Nightingale-Wren
- Southern Rough-winged Swallow
- Southern Royal Albatross
- Southern Screamer
- Southern Scrub Flycatcher
- Southern White-fringed Antwren
- Spangle-cheeked Tanager
- Spangled Coquette
- Spangled Cotinga
- Spangled Drongo
- Sparkling Violetear
- Speckled Hummingbird
- Speckled Piculet
- Speckled Tanager
- Spectacled Fulvetta
- Spectacled Thrush
- Spectacled Tyrannulet
- Spectacled Tyrant
- Spectacled Whitestart
- Spot-billed Ground Tyrant
- Spot-billed Toucanet
- Spot-breasted Antvireo
- Spot-breasted Woodpecker
- Spot-breasted Wren
- Spot-crowned Euphonia
- Spot-flanked Gallinule
- Spot-winged Antbird
- Spot-winged Falconet
- Spot-winged Pigeon
- Spotted Nutcracker
- Spotted Puffbird
- Spotted Sandpiper
- Spotted Tanager
- Spotted Tody-Flycatcher
- Spotted Whistling Duck
- Spotted Woodcreeper
- Spruce Grouse
- Squirrel Cuckoo
- St. Lucia Amazon
- St. Lucia Black Finch
- St. Lucia Oriole
- St. Lucia Warbler
- St. Vincent Amazon
- Steely-vented Hummingbird
- Stejneger's Stonechat
- Steller's Jay
- Stephan's Emerald Dove
- Stilt Sandpiper
- Stolid Flycatcher
- Stout-billed Cinclodes
- Straight-billed Earthcreeper
- Straight-billed Woodcreeper
- Streak-backed Canastero
- Streak-backed Oriole
- Streak-backed Tit-Spinetail
- Streak-breasted Scimitar Babbler
- Streak-chested Antpitta
- Streak-eared Bulbul
- Streak-fronted Thornbird
- Streak-headed Honeyeater
- Streak-headed Woodcreeper
- Streak-throated Bush Tyrant
- Streaked Flycatcher
- Streaked Saltator
- Streaked Spiderhunter
- Streaked Tuftedcheek
- Streaked Xenops
- Striated Grassbird
- Striated Heron
- Strickland's Woodpecker
- Stripe-backed Bittern
- Stripe-breasted Wren
- Stripe-capped Sparrow
- Stripe-crowned Spinetail
- Stripe-headed Rhabdornis
- Stripe-headed Sparrow
- Stripe-necked Tody-Tyrant
- Stripe-tailed Hummingbird
- Stripe-throated Bulbul
- Stripe-throated Yuhina
- Striped Cuckoo
- Striped Owl
- Striped Woodcreeper
- Striped Woodpecker
- Strong-billed Woodcreeper
- Subdesert Mesite
- Suiriri Flycatcher
- Sulphur-bellied Flycatcher
- Sulphur-rumped Myiobius
- Sulphury Flycatcher
- Sultan Tit
- Summer Tanager
- Sunbittern
- Sunda Laughingthrush
- Sunda Pygmy Woodpecker
- Superb Fruit Dove
- Superciliaried Hemispingus
- Surf Scoter
- Surfbird
- Surucua Trogon
- Swainson's Flycatcher
- Swainson's Thrush
- Swallow-tailed Cotinga
- Swallow-tailed Gull
- Swallow-tailed Hummingbird
- Swallow-tailed Kite
- Swallow-winged Puffbird
- Swallow Tanager
- Swamp Sparrow
- Sword-billed Hummingbird