- Sabine's Gull
- Sanderling
- Savannah Sparrow
- Scopoli's Shearwater
- Short-eared Owl
- Short-toed Treecreeper
- Snow Bunting
- Snow Petrel
- Snowy Albatross
- Snowy Sheathbill
- Song Sparrow
- Song Thrush
- Sooty Shearwater
- South Georgia Shag
- Southern Fulmar
- Southern Giant Petrel
- Southern Lapwing
- Southern Rockhopper Penguin
- Southern Royal Albatross
- Spotted Crake
- Spotted Flycatcher
- Steller's Eider
- Striated Caracara