- Sacred Kingfisher
- Saddle-billed Stork
- Saffron-crowned Tanager
- Sanderling
- Sandwich Tern
- Sardinian Warbler
- Sargasso Shearwater
- Sarus Crane
- Savannah Sparrow
- Say's Phoebe
- Sayaca Tanager
- Scale-crested Pygmy Tyrant
- Scale-throated Earthcreeper
- Scaly-breasted Munia
- Scaly-breasted Thrasher
- Scarlet-chested Sunbird
- Scarlet-rumped Cacique
- Scarlet-rumped Tanager
- Scarlet-rumped Tanager (costaricensis)
- Scarlet Macaw
- Scissor-tailed Kite
- Screaming Cowbird
- Secretarybird
- Sedge Warbler
- Semipalmated Plover
- Semipalmated Sandpiper
- Senegal Coucal
- Senegal Eremomela
- Senegal Lapwing
- Senegal Parrot
- Senegal Thick-knee
- Shining Bronze Cuckoo
- Shiny Cowbird
- Short-billed Dowitcher
- Short-billed Pigeon
- Short-eared Owl
- Short-toed Rock Thrush
- Short-toed Snake Eagle
- Short-toed Treecreeper
- Siberian Thrush
- Silver-backed Needletail
- Silver-beaked Tanager
- Silver-eared Mesia
- Silver-throated Tanager
- Silver Gull (scopulinus)
- Silvereye
- Silvery-cheeked Hornbill
- Silvery Grebe
- Slate-colored Boubou
- Slate-throated Whitestart
- Slaty-backed Forktail
- Slaty-tailed Trogon
- Slaty Flowerpiercer
- Slender-billed Finch
- Slender-billed Gull
- Slender-tailed Nightjar
- Small Ground Finch
- Smew
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Goose
- Snow Pigeon
- Snowy Cotinga
- Snowy Egret
- Social Flycatcher
- Solitary Sandpiper
- Somali Crow
- Somali Fiscal
- Sombre Greenbul
- Song Sparrow
- Song Thrush
- Sooty Thrush
- Souimanga Sunbird
- South African Shelduck
- South American Tern
- South Island Oystercatcher
- Southern Beardless Tyrannulet
- Southern Boubou
- Southern Double-collared Sunbird
- Southern Giant Petrel
- Southern Grey-headed Sparrow
- Southern Ground Hornbill
- Southern House Wren
- Southern Lapwing
- Southern Masked Weaver
- Southern Pied Babbler
- Southern Pochard
- Southern Red-billed Hornbill
- Southern Red Bishop
- Southern Rough-winged Swallow
- Southern Yellow-billed Hornbill
- Spanish Sparrow
- Sparkling Violetear
- Speckle-fronted Weaver
- Speckled Chachalaca
- Speckled Mousebird
- Speckled Pigeon
- Speckled Tanager
- Spectacled Owl
- Spectacled Thrush
- Spectacled Tyrant
- Spectacled Warbler
- Spectacled Weaver
- Spot-billed Pelican
- Spot-breasted Lapwing
- Spot-breasted Oriole
- Spot-flanked Barbet
- Spotless Starling
- Spotted Antbird
- Spotted Dove
- Spotted Eagle-Owl
- Spotted Flycatcher
- Spotted Owlet
- Spotted Palm Thrush
- Spotted Redshank
- Spotted Sandpiper
- Spotted Shag
- Spotted Thick-knee
- Spruce Grouse
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Square-tailed Drongo
- Square-tailed Drongo-Cuckoo
- Squirrel Cuckoo
- Sri Lanka Green Pigeon
- Steller's Jay
- Stork-billed Kingfisher
- Straw-tailed Whydah
- Streak-backed Oriole
- Streak-breasted Treehunter
- Streak-headed Woodcreeper
- Streak-throated Canastero
- Streaked Flycatcher
- Streaked Saltator
- Streaked Spiderhunter
- Streaky-headed Seedeater
- Streaky Seedeater
- Striated Earthcreeper
- Striated Heron
- Stripe-headed Sparrow
- Stripe-tailed Hummingbird
- Striped Kingfisher
- Stuhlmann's Starling
- Sudan Golden Sparrow
- Sulphur-bellied Flycatcher
- Sultan Tit
- Summer Tanager
- Superb Starling
- Swainson's Hawk
- Swainson's Sparrow
- Swainson's Spurfowl
- Swallow-tailed Gull
- Syrian Woodpecker