- Saffron-crowned Tanager
- Saffron Finch
- Sapphire-spangled Emerald
- Savanna Hawk
- Savi's Warbler
- Scale-crested Pygmy Tyrant
- Scarlet-backed Woodpecker
- Scarlet-bellied Mountain Tanager
- Scrub Blackbird
- Semipalmated Plover
- Semipalmated Sandpiper
- Senegal Eremomela
- Senegal Thick-knee
- Shikra
- Shining Sunbeam
- Shiny Cowbird
- Short-eared Owl
- Short-tailed Field Tyrant
- Sierran Elaenia
- Silver-beaked Tanager
- Silvery Grebe
- Slaty-backed Chat-Tyrant
- Slaty Becard
- Slaty Brushfinch
- Slender-billed Miner
- Slender-billed Parakeet
- Smoky Bush Tyrant
- Smooth-billed Ani
- Snail Kite
- Snowy-throated Kingbird
- Snowy Egret
- Snowy Plover
- Social Flycatcher
- Sooty-crowned Flycatcher
- Sooty Shearwater
- Southern Beardless Tyrannulet
- Southern Lapwing
- Southern Mouse-colored Tyrannulet
- Southern Rough-winged Swallow
- Southern Tropical Pewee
- Sparkling Violetear
- Speckled Chachalaca
- Speckled Hummingbird
- Speckled Pigeon
- Spectacled Owl
- Spectacled Tyrant
- Spectacled Whitestart
- Spot-throated Hummingbird
- Spot-winged Pigeon
- Spotted Flycatcher
- Spotted Sandpiper
- Spotted Tody-Flycatcher
- Spur-winged Lapwing
- Squirrel Cuckoo
- Stone Partridge
- Straight-billed Woodcreeper
- Streak-backed Canastero
- Streak-headed Woodcreeper
- Streak-throated Canastero
- Streaked Saltator
- Striated Earthcreeper
- Striated Heron
- Stripe-headed Antpitta
- Striped Cuckoo
- Strong-billed Woodcreeper
- Sunbittern
- Superciliated Wren
- Surfbird
- Swallow-tailed Gull