- Sabine's Gull
- Sabota Lark
- Sabota Lark (naevia)
- Saddle-billed Stork
- Saffron-crowned Tanager
- Saffron Finch
- Sanderling
- Sapphire-spangled Emerald
- Sapphire-vented Puffleg
- Sardinian Warbler
- Savanna Hawk
- Savi's Warbler
- Saw-billed Hermit
- Scale-crested Pygmy Tyrant
- Scale-throated Earthcreeper
- Scale-throated Hermit
- Scaled Antbird
- Scaled Chachalaca
- Scaled Fruiteater
- Scaly-breasted Munia
- Scaly-feathered Weaver
- Scaly-headed Parrot
- Scarlet-backed Flowerpecker
- Scarlet-bellied Mountain Tanager
- Scarlet-chested Sunbird
- Scarlet-rumped Tanager
- Scarlet-rumped Tanager (costaricensis)
- Scarlet Flycatcher
- Scarlet Macaw
- Scimitar-billed Woodcreeper
- Scintillant Hummingbird
- Sclater's Tyrannulet
- Scopoli's Shearwater
- Screaming Cowbird
- Screaming Piha
- Secretarybird
- Semipalmated Plover
- Sepia-capped Flycatcher
- Sharp-tailed Streamcreeper
- Shikra
- Shining Honeycreeper
- Shining Sunbeam
- Shiny Cowbird
- Short-billed Pigeon
- Short-billed Pipit
- Short-crested Flycatcher
- Short-tailed Hawk
- Short-tailed Woodstar
- Short-toed Rock Thrush
- Short-toed Treecreeper
- Siamese Pied Myna
- Siberian Rubythroat (beicki)
- Siberian Stonechat
- Sierran Elaenia
- Silver-backed Tanager
- Silver-beaked Tanager
- Silver-throated Tanager
- Silver Pheasant
- Silver Teal
- Silvered Antbird
- Slate-throated Whitestart
- Slaty-backed Gull
- Slaty-breasted Wood Rail
- Slaty-capped Flycatcher
- Slaty-tailed Trogon
- Slaty Antwren
- Slaty Becard
- Slaty Bristlefront
- Slaty Flowerpiercer
- Slender-billed Gull
- Slender-footed Tyrannulet
- Small-billed Elaenia
- Smoke-colored Pewee
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snowy Egret
- Snowy Owl
- Snowy Plover
- Sociable Weaver
- Social Flycatcher
- Solitary Eagle
- Solitary Tinamou
- Sombre Hummingbird
- Sooty-capped Chlorospingus
- Sooty-fronted Spinetail
- Sooty-headed Bulbul
- Sooty Shearwater
- South African Shelduck
- South American Tern
- Southern Beardless Tyrannulet
- Southern Boubou
- Southern Fiscal
- Southern Grey-headed Sparrow
- Southern Ground Hornbill
- Southern House Wren
- Southern Lapwing
- Southern Martin
- Southern Masked Weaver
- Southern Pochard
- Southern Red-billed Hornbill
- Southern Red-fronted Tinkerbird
- Southern Rough-winged Swallow
- Southern White-crowned Shrike
- Southern Yellow-billed Hornbill
- Sparkling Violetear
- Speckled Chachalaca
- Speckled Hummingbird
- Speckled Mousebird
- Speckled Piculet
- Speckled Pigeon
- Spectacled Tyrant
- Spectacled Warbler
- Spectacled Whitestart
- Spike-heeled Lark
- Spix's Guan
- Spot-billed Pelican
- Spot-breasted Antvireo
- Spot-crowned Woodcreeper
- Spot-winged Antbird
- Spot-winged Falconet
- Spot-winged Pigeon
- Spot-winged Wood Quail
- Spotted Dove
- Spotted Eagle-Owl
- Spotted Sandpiper
- Spotted Tanager
- Spotted Woodcreeper
- Squamate Antbird
- Squirrel Cuckoo
- Star-throated Antwren
- Steller's Eider
- Stout-billed Cinclodes
- Straight-billed Woodcreeper
- Straneck's Tyrannulet
- Streak-backed Canastero
- Streak-breasted Scimitar Babbler
- Streak-capped Antwren
- Streak-eared Bulbul
- Streak-headed Woodcreeper
- Streak-necked Flycatcher
- Streak-throated Canastero
- Streaked Dacnis
- Streaked Flycatcher
- Streaked Xenops
- Striated Heron
- Stripe-crowned Spinetail
- Stripe-headed Antpitta
- Stripe-tailed Hummingbird
- Striped Kingfisher
- Striped Pipit
- Subtropical Cacique
- Summer Tanager
- Sungrebe
- Superciliaried Hemispingus
- Superciliated Wren
- Swainson's Spurfowl
- Swainson's Thrush
- Swallow-tailed Kite
- Swallow-winged Puffbird
- Sword-billed Hummingbird
- Syrian Woodpecker