- Sabine's Gull
- Saddle-billed Stork
- Saffron-crowned Tanager
- Saffron Finch
- Sahel Bush Sparrow
- Sahul Sunbird
- Sand Martin
- Sanderling
- Sandwich Tern
- Santa Marta Antpitta
- Santa Marta Brushfinch
- Santa Marta Parakeet
- Santa Marta Woodstar
- Sardinian Warbler
- Saunders's Tern
- Savanna Hawk
- Savile's Bustard
- Sayaca Tanager
- Scaled Dove
- Scaled Piculet
- Scaled Pigeon
- Scaly-breasted Munia
- Scarlet-backed Woodpecker
- Scarlet-chested Sunbird
- Scarlet-headed Blackbird
- Scarlet-rumped Tanager
- Scarlet-rumped Tanager (costaricensis)
- Scarlet-thighed Dacnis
- Scarlet Flycatcher
- Scarlet Macaw
- Scarlet Minivet
- Scintillant Hummingbird
- Scissor-tailed Flycatcher
- Scissor-tailed Kite
- Scrub Tanager
- Sedge Warbler
- Semipalmated Sandpiper
- Semiplumbeous Hawk
- Senegal Coucal
- Senegal Eremomela
- Senegal Parrot
- Senegal Thick-knee
- Sharp-tailed Grass Tyrant
- Shikra
- Shining-blue Kingfisher
- Shining Honeycreeper
- Shining Sunbeam
- Shiny Cowbird
- Short-billed Pigeon
- Short-crested Flycatcher
- Short-tailed Hawk
- Short-toed Snake Eagle
- Short-toed Treecreeper
- Shrike-like Tanager
- Sickle-winged Guan
- Silver-beaked Tanager
- Silver-throated Tanager
- Silvery Grebe
- Singing Starling
- Slate-throated Whitestart
- Slaty-backed Chat-Tyrant
- Slaty-backed Nightingale-Thrush
- Slaty-crowned Antpitta
- Slaty-tailed Trogon
- Slaty Flowerpiercer
- Slender-billed Gull
- Slender-billed Inezia
- Slender-footed Tyrannulet
- Smooth-billed Ani
- Snail Kite
- Snow Bunting
- Snow Goose
- Snow Petrel
- Snowy-bellied Hummingbird
- Snowy Cotinga
- Snowy Egret
- Social Flycatcher
- Socotra Cormorant
- Solitary Cacique
- Solitary Sandpiper
- Song Sparrow
- Song Thrush
- Sooty-capped Chlorospingus
- Sooty-crowned Flycatcher
- Sooty-fronted Spinetail
- Sooty-headed Tyrannulet
- Sooty Falcon
- Sooty Gull
- Sooty Thrush
- Southern Beardless Tyrannulet
- Southern Giant Petrel
- Southern Ground Hornbill
- Southern Lapwing
- Southern Rough-winged Swallow
- Southern Screamer
- Spanish Imperial Eagle
- Spanish Sparrow
- Sparkling Violetear
- Speckle-fronted Weaver
- Speckled Chachalaca
- Speckled Hummingbird
- Speckled Pigeon
- Speckled Tanager
- Spectacled Owl
- Spectacled Warbler
- Spot-breasted Oriole
- Spotless Starling
- Spotted Dove
- Spotted Flycatcher
- Spotted Nutcracker
- Spotted Sandgrouse
- Spotted Sandpiper
- Spotted Woodcreeper
- Spur-winged Goose
- Spur-winged Lapwing
- Squacco Heron
- Squirrel Cuckoo
- Standard-winged Nightjar
- Steely-vented Hummingbird
- Steppe Eagle
- Stock Dove
- Stone Partridge
- Stork-billed Kingfisher
- Stout-billed Cinclodes
- Straight-billed Woodcreeper
- Streak-headed Woodcreeper
- Streaked Flycatcher
- Streaked Rosefinch
- Streaked Saltator
- Streaked Scrub Warbler
- Streamer-tailed Tyrant
- Striated Heron
- Stripe-headed Sparrow
- Stripe-throated Hermit
- Stripe-throated Yuhina
- Striped Cuckoo
- Strong-billed Woodcreeper
- Sudan Golden Sparrow
- Sulphur-crested Cockatoo
- Summer Tanager
- Sunbittern
- Sunda Pygmy Woodpecker
- Sunda Zebra Finch
- Sungrebe
- Superb Starling
- Superciliaried Hemispingus
- Swallow-tailed Kite
- Swallow-winged Puffbird
- Swallow Tanager
- Swamp Flycatcher
- Swamp Sparrow
- Sword-billed Hummingbird