| View | Acanthis flammea | Redpoll | |
| View | Accipiter striatus | Sharp-shinned Hawk | |
| View | Actitis macularius | Spotted Sandpiper | |
| View | Aechmophorus clarkii | Clark's Grebe | |
| View | Aechmophorus occidentalis | Western Grebe | |
| View | Aegolius acadicus | Northern Saw-whet Owl | |
| View | Aeronautes saxatalis | White-throated Swift | |
| View | Agelaius phoeniceus | Red-winged Blackbird | |
| View | Aix sponsa | Wood Duck | |
| View | Alca torda | Razorbill | |
| View | Alle alle | Dovekie | |
| View | Amazilia yucatanensis | Buff-bellied Hummingbird | |
| View | Ammodramus savannarum | Grasshopper Sparrow | |
| View | Ammospiza caudacuta | Saltmarsh Sparrow | |
| View | Ammospiza leconteii | LeConte's Sparrow | |
| View | Ammospiza maritima | Seaside Sparrow | |
| View | Ammospiza nelsoni | Nelson's Sparrow | |
| View | Anarhynchus montanus | Mountain Plover | |
| View | Anarhynchus nivosus | Snowy Plover | |
| View | Anarhynchus wilsonia | Wilson's Plover | |
| View | Anas acuta | Northern Pintail | |
| View | Anas bahamensis | White-cheeked Pintail | |
| View | Anas crecca | Green-winged Teal | |
| View | Anas fulvigula | Mottled Duck | |
| View | Anas platyrhynchos | Mallard | |
| View | Anas rubripes | American Black Duck | |
| View | Anhinga anhinga | Anhinga | |
| View | Anous stolidus | Brown Noddy | |
| View | Anser albifrons | Greater White-fronted Goose | |
| View | Anser caerulescens | Snow Goose | |
| View | Anser rossii | Ross's Goose | |
| View | Anthracothorax prevostii | Green-breasted Mango | |
| View | Anthus rubescens | American Pipit | |
| View | Anthus spragueii | Sprague's Pipit | |
| View | Antigone canadensis | Sandhill Crane | |
| View | Antrostomus carolinensis | Chuck-will's-widow | |
| View | Antrostomus vociferus | Eastern Whip-poor-will | |
| View | Apus apus | Common Swift | |
| View | Aquila chrysaetos | Golden Eagle | |
| View | Aramus guarauna | Limpkin | |
| View | Archilochus alexandri | Black-chinned Hummingbird | |
| View | Archilochus colubris | Ruby-throated Hummingbird | |
| View | Ardea alba | Great Egret | |
| View | Ardea herodias | Great Blue Heron | |
| View | Ardea ibis | Western Cattle-Egret | |
| View | Ardenna gravis | Great Shearwater | |
| View | Ardenna grisea | Sooty Shearwater | |
| View | Ardenna pacifica | Wedge-tailed Shearwater | |
| View | Arenaria interpres | Ruddy Turnstone | |
| View | Asio flammeus | Short-eared Owl | |
| View | Asio otus | Long-eared Owl | |
| View | Astur atricapillus | American Goshawk | |
| View | Astur cooperii | Cooper's Hawk | |
| View | Athene cunicularia | Burrowing Owl | |
| View | Aythya affinis | Lesser Scaup | |
| View | Aythya americana | Redhead | |
| View | Aythya collaris | Ring-necked Duck | |
| View | Aythya fuligula | Tufted Duck | |
| View | Aythya marila | Greater Scaup | |
| View | Aythya valisineria | Canvasback |