- Sabine's Gull
- Sabine's Puffback
- Sacred Kingfisher
- Saffron Finch
- Sahel Bush Sparrow
- Sahel Paradise Whydah
- Sahul Brush Cuckoo
- Sand Martin
- Sanderling
- Sandhill Crane
- Sandwich Tern
- Santa Marta Antpitta
- Santa Marta Brushfinch
- Santa Marta Bush Tyrant
- Santa Marta Mountain Tanager
- Santa Marta Warbler
- Santa Marta Woodstar
- Sardinian Warbler
- Savanna Hawk
- Savi's Warbler
- Savile's Bustard
- Saxaul Sparrow
- Scale-crested Pygmy Tyrant
- Scaled Dove
- Scaled Fruiteater
- Scaled Piculet
- Scaled Pigeon
- Scaly-breasted Munia
- Scaly-naped Amazon
- Scaly-sided Merganser
- Scarlet-backed Flowerpecker
- Scarlet-chested Sunbird
- Scarlet-rumped Tanager
- Scarlet-rumped Tanager (costaricensis)
- Scarlet-thighed Dacnis
- Scarlet Macaw
- Scintillant Hummingbird
- Scissor-tailed Flycatcher
- Scissor-tailed Kite
- Sclater's Whistler
- Scopoli's Shearwater
- Screaming Piha
- Scrub Euphonia
- Scrub Greenlet
- Scrub Tanager
- Sedge Warbler
- Semipalmated Plover
- Semipalmated Sandpiper
- Senegal Coucal
- Senegal Eremomela
- Senegal Parrot
- Senegal Thick-knee
- Sharpe's Apalis
- Shikra
- Shining-blue Kingfisher
- Shining Flycatcher
- Shining Honeycreeper
- Shining Sunbeam
- Shiny Cowbird
- Short-billed Pigeon
- Short-crested Flycatcher
- Short-eared Owl
- Short-tailed Hawk
- Short-tailed Nighthawk
- Short-tailed Woodstar
- Short-toed Snake Eagle
- Short-toed Treecreeper
- Shy Albatross
- Siberian Stonechat
- Sickle-winged Chat
- Sickle-winged Guan
- Sierra Nevada Brushfinch
- Silver-beaked Tanager
- Silver-throated Tanager
- Silvery Grebe
- Simple Greenbul
- Singing Starling
- Slate-throated Whitestart
- Slaty-backed Chat-Tyrant
- Slaty-crowned Antpitta
- Slaty-tailed Trogon
- Slaty Brushfinch
- Slaty Flowerpiercer
- Slaty Robin
- Slender-billed Greenbul
- Slender-billed Gull
- Small Minivet
- Smew
- Smoke-colored Pewee
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snowy-bellied Hummingbird
- Snowy Cotinga
- Snowy Egret
- Snowy Owl
- Sociable Lapwing
- Social Flycatcher
- Solitary Eagle
- Sombre Greenbul
- Song Sparrow
- Song Thrush
- Sooty-capped Chlorospingus
- Sooty-headed Bulbul
- Sooty Shearwater
- South African Shelduck
- Southern Beardless Tyrannulet
- Southern Black Korhaan
- Southern Boubou
- Southern Double-collared Sunbird
- Southern Fiscal
- Southern Giant Petrel
- Southern Lapwing
- Southern Masked Weaver
- Southern Pochard
- Southern Red Bishop
- Southern Rough-winged Swallow
- Southern Tchagra
- Spangle-cheeked Tanager
- Spangled Drongo
- Spanish Sparrow
- Sparkling Violetear
- Speckled Hummingbird
- Speckled Mousebird
- Speckled Pigeon
- Speckled Tanager
- Speckled Tinkerbird
- Spectacled Owl
- Spectacled Warbler
- Spectacled Whitestart
- Splendid Starling
- Spot-billed Pelican
- Spot-breasted Oriole
- Spot-breasted Woodpecker
- Spot-breasted Wren
- Spot-crowned Euphonia
- Spot-winged Antbird
- Spot-winged Thrush
- Spotless Starling
- Spotted Antbird
- Spotted Crake
- Spotted Dove
- Spotted Eagle-Owl
- Spotted Flycatcher
- Spotted Redshank
- Spotted Sandpiper
- Spotted Thick-knee
- Spotted Tody-Flycatcher
- Spotted Towhee
- Spotted Whistling Duck
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Square-tailed Bulbul
- Square-tailed Saw-wing
- Squirrel Cuckoo
- Sri Lanka Blue Magpie
- Sri Lanka Drongo
- Sri Lanka Frogmouth
- Sri Lanka Green Pigeon
- Sri Lanka Grey Hornbill
- Sri Lanka Hanging Parrot
- Sri Lanka Hill Myna
- Sri Lanka Junglefowl
- Sri Lanka Scimitar Babbler
- Sri Lanka Swallow
- Sri Lanka Whistling Thrush
- Sri Lanka White-eye
- Sri Lanka Wood Pigeon
- Sri Lanka Woodshrike
- Steely-vented Hummingbird
- Steller's Jay
- Steppe Eagle
- Stilt Sandpiper
- Stone Partridge
- Stout-billed Cinclodes
- Straight-billed Hermit
- Straight-billed Woodcreeper
- Streak-eared Bulbul
- Streak-headed Woodcreeper
- Streak-throated Bush Tyrant
- Streaked Flycatcher
- Streaked Saltator
- Streaked Weaver
- Streaky-headed Seedeater
- Striated Heron
- Stripe-backed Wren
- Stripe-throated Hermit
- Striped Cuckoo
- Striped Kingfisher
- Strong-billed Woodcreeper
- Sudan Golden Sparrow
- Sulphur-crested Cockatoo
- Summer Tanager
- Sun Lark
- Sunda Pygmy Woodpecker
- Sunda Teal
- Superb Sunbird
- Superciliated Wren
- Surf Scoter
- Swainson's Thrush
- Swallow-tailed Bee-eater
- Swallow-tailed Kite
- Swallow Tanager
- Swamp Flycatcher
- Swan Goose
- Sword-billed Hummingbird
- Sykes's Warbler
- Syrian Woodpecker