| View | Xema sabini | Sabine's Gull | |
| View | Oreoscoptes montanus | Sage Thrasher | |
| View | Ammospiza caudacuta | Saltmarsh Sparrow | |
| View | Calidris alba | Sanderling | |
| View | Antigone canadensis | Sandhill Crane | |
| View | Thalasseus sandvicensis | Sandwich Tern | |
| View | Puffinus lherminieri | Sargasso Shearwater | |
| View | Passerculus sandwichensis | Savannah Sparrow | |
| View | Sayornis saya | Say's Phoebe | |
| View | Piranga olivacea | Scarlet Tanager | |
| View | Tyrannus forficatus | Scissor-tailed Flycatcher | |
| View | Calonectris diomedea | Scopoli's Shearwater | |
| View | Icterus parisorum | Scott's Oriole | |
| View | Ammospiza maritima | Seaside Sparrow | |
| View | Cistothorus stellaris | Sedge Wren | |
| View | Charadrius semipalmatus | Semipalmated Plover | |
| View | Calidris pusilla | Semipalmated Sandpiper | |
| View | Accipiter striatus | Sharp-shinned Hawk | |
| View | Calidris acuminata | Sharp-tailed Sandpiper | |
| View | Molothrus bonariensis | Shiny Cowbird | |
| View | Limnodromus griseus | Short-billed Dowitcher | |
| View | Larus brachyrhynchus | Short-billed Gull | |
| View | Asio flammeus | Short-eared Owl | |
| View | Larus schistisagus | Slaty-backed Gull | |
| View | Calcarius pictus | Smith's Longspur | |
| View | Crotophaga ani | Smooth-billed Ani | |
| View | Rostrhamus sociabilis | Snail Kite | |
| View | Plectrophenax nivalis | Snow Bunting | |
| View | Anser caerulescens | Snow Goose | |
| View | Egretta thula | Snowy Egret | |
| View | Bubo scandiacus | Snowy Owl | |
| View | Anarhynchus nivosus | Snowy Plover | |
| View | Tringa solitaria | Solitary Sandpiper | |
| View | Melospiza melodia | Song Sparrow | |
| View | Ardenna grisea | Sooty Shearwater | |
| View | Onychoprion fuscatus | Sooty Tern | |
| View | Porzana carolina | Sora | |
| View | Stercorarius maccormicki | South Polar Skua | |
| View | Tringa erythropus | Spotted Redshank | |
| View | Actitis macularius | Spotted Sandpiper | |
| View | Pipilo maculatus | Spotted Towhee | |
| View | Anthus spragueii | Sprague's Pipit | |
| View | Calidris himantopus | Stilt Sandpiper | |
| View | Piranga rubra | Summer Tanager | |
| View | Melanitta perspicillata | Surf Scoter | |
| View | Buteo swainsoni | Swainson's Hawk | |
| View | Catharus ustulatus | Swainson's Thrush | |
| View | Limnothlypis swainsonii | Swainson's Warbler | |
| View | Elanoides forficatus | Swallow-tailed Kite | |
| View | Melospiza georgiana | Swamp Sparrow | |
| View | Hydrobates monorhis | Swinhoe's Storm-Petrel |