- Sabine's Gull
- Sabota Lark
- Saddle-billed Stork
- Saffron-billed Sparrow
- Saffron Finch
- Saker Falcon
- Sand Martin
- Sanderling
- Sandwich Tern
- Sardinian Warbler
- Sarus Crane
- Savanna Hawk
- Savannah Sparrow
- Savi's Warbler
- Sayaca Tanager
- Scaly-headed Parrot
- Scarlet-chested Sunbird
- Scarlet-headed Blackbird
- Scarlet Flycatcher
- Scopoli's Shearwater
- Screaming Cowbird
- Secretarybird
- Sedge Warbler
- Semipalmated Plover
- Semipalmated Sandpiper
- Shikra
- Shiny Cowbird
- Short-billed Canastero
- Short-billed Dowitcher
- Short-billed Pipit
- Short-eared Owl
- Short-toed Snake Eagle
- Short-toed Treecreeper
- Siberian Jay
- Silver Teal
- Silvery Grebe
- Sirkeer Malkoha
- Slender-billed Gull
- Small Minivet
- Smew
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Goose
- Snowy-crowned Tern
- Snowy Owl
- Snowy Sheathbill
- Sociable Lapwing
- Social Flycatcher
- Solitary Cacique
- Sombre Greenbul
- Sombre Tit
- Song Sparrow
- Song Thrush
- South African Shelduck
- South American Tern
- Southern Bald Ibis
- Southern Banded Snake Eagle
- Southern Black Flycatcher
- Southern Black Tit
- Southern Fiscal
- Southern Grey-headed Sparrow
- Southern Ground Hornbill
- Southern House Wren
- Southern Lapwing
- Southern Masked Weaver
- Southern Red-fronted Tinkerbird
- Southern Rough-winged Swallow
- Southern Screamer
- Southern White-crowned Shrike
- Southern Yellow-billed Hornbill
- Southern Yellowthroat
- Spanish Imperial Eagle
- Spanish Sparrow
- Speckled Mousebird
- Speckled Pigeon
- Spectacled Tyrant
- Spectacled Warbler
- Spectacled Weaver
- Spot-flanked Gallinule
- Spot-winged Pigeon
- Spotless Starling
- Spotted Crake
- Spotted Dove
- Spotted Flycatcher
- Spotted Nothura
- Spotted Owlet
- Spotted Redshank
- Spotted Sandpiper
- Spruce Grouse
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Square-tailed Drongo
- Squirrel Cuckoo
- Steller's Eider
- Stock Dove
- Strange-tailed Tyrant
- Streak-throated Bush Tyrant
- Streaked Flycatcher
- Striated Heron
- Striped Cuckoo
- Striped Kingfisher
- Striped Owl
- Surf Scoter
- Surucua Trogon
- Swainson's Spurfowl
- Swainson's Thrush
- Swallow-tailed Hummingbird
- Swallow-tailed Kite
- Swallow Tanager
- Swamp Sparrow
- Syrian Woodpecker