- Sabine's Gull
- Sacred Kingfisher
- Saddle-billed Stork
- Saffron Finch
- Saker Falcon
- Sanderling
- Sandhill Crane
- Sandwich Tern
- Sardinian Warbler
- Sarus Crane
- Savanna Hawk
- Sayaca Tanager
- Scaled Dove
- Scaly-feathered Weaver
- Scaly Ground Roller
- Scaly Spurfowl
- Scarlet-chested Sunbird
- Scarlet Flycatcher
- Scarlet Macaw
- Scarlet Robin
- Schlegel's Asity
- Scopoli's Shearwater
- Secretarybird
- Semipalmated Plover
- Senegal Lapwing
- Senegal Thick-knee
- Shaft-tailed Whydah
- Shikra
- Shining Flycatcher
- Shiny Cowbird
- Shoebill
- Short-toed Rock Thrush
- Short-toed Snake Eagle
- Sichuan Leaf Warbler
- Sickle-billed Vanga
- Silver Gull
- Silvereye
- Silvery-cheeked Hornbill
- Singing Cisticola
- Slate-colored Boubou
- Slaty Bunting
- Slender-billed Gull
- Slender-billed Weaver
- Slender-tailed Nightjar
- Small Ground Finch
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Pigeon
- Snowy-crowned Robin-Chat
- Snowy Egret
- Snowy Sheathbill
- Soft-plumaged Petrel
- Somali Bee-eater
- Somali Courser
- Somali Ostrich
- Sombre Greenbul
- Song Sparrow
- Song Thrush
- Sooty Albatross
- Sooty Bushtit
- Sooty Chat
- Sooty Oystercatcher
- Sooty Shearwater
- Souimanga Sunbird
- South American Tern
- South Polar Skua
- Southern Black Korhaan
- Southern Carmine Bee-eater
- Southern Cassowary
- Southern Crested Caracara
- Southern Fiscal
- Southern Fulmar
- Southern Giant Petrel
- Southern Grey-headed Sparrow
- Southern Ground Hornbill
- Southern Lapwing
- Southern Masked Weaver
- Southern Pied Babbler
- Southern Pochard
- Southern Red-billed Hornbill
- Southern Red Bishop
- Southern Rough-winged Swallow
- Southern Royal Albatross
- Southern Screamer
- Southern White-crowned Shrike
- Southern Yellow-billed Hornbill
- Spanish Imperial Eagle
- Speckle-fronted Weaver
- Speckle-throated Woodpecker
- Speckled Mousebird
- Speckled Pigeon
- Speckled Tinkerbird
- Spectacled Weaver
- Speke's Weaver
- Spike-heeled Lark
- Spix's Spinetail
- Spotless Starling
- Spotted Crake
- Spotted Eagle-Owl
- Spotted Flycatcher
- Spotted Nothura
- Spotted Owlet
- Spotted Palm Thrush
- Spotted Redshank
- Spotted Sandpiper
- Spotted Thick-knee
- Spruce Grouse
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Square-tailed Nightjar
- Squatter Pigeon
- Squirrel Cuckoo
- Steel-blue Whydah
- Steller's Jay
- Steppe Eagle
- Stork-billed Kingfisher
- Stout Cisticola
- Straw-necked Ibis
- Streaked Xenops
- Streaky Seedeater
- Streamer-tailed Tyrant
- Striated Heron
- Stripe-throated Jery
- Striped Kingfisher
- Subalpine Warbler
- Subdesert Mesite
- Sulphur-crested Cockatoo
- Sunbittern
- Superb Fairywren
- Superb Starling
- Surf Scoter
- Surucua Trogon
- Swahili Sparrow
- Swainson's Spurfowl
- Swallow-tailed Bee-eater
- Swallow Tanager
- Swamp Flycatcher