Confused pairs
Incorrect answers between two species (undirected). With a country selected, only mix-ups from games in that country are counted, and only pairs where both species are on that country's checklist are shown.
| Species A (lower id) | Species B (higher id) | Total wrong | A was target → picked B | B was target → picked A |
|---|---|---|---|---|
| Snow Goose Anser caerulescens | Ross's Goose Anser rossii | 5 | 2 | 3 |
| Canada Goose Branta canadensis | Common Raven Corvus corax | 4 | 2 | 2 |
| Common Gull Larus canus | Short-billed Gull Larus brachyrhynchus | 2 | 1 | 1 |
| Black-necked Stilt Himantopus mexicanus | Grey Plover Pluvialis squatarola | 2 | 2 | 0 |
| Least Sandpiper Calidris minutilla | Semipalmated Sandpiper Calidris pusilla | 2 | 1 | 1 |
| Least Flycatcher Empidonax minimus | Western Flycatcher Empidonax difficilis | 2 | 1 | 1 |
| Swainson's Hawk Buteo swainsoni | Rough-legged Buzzard Buteo lagopus | 2 | 1 | 1 |
| Canada Goose Branta canadensis | Canada Jay Perisoreus canadensis | 2 | 2 | 0 |
| Cackling Goose Branta hutchinsii | Canada Goose Branta canadensis | 2 | 1 | 1 |
| Common Raven Corvus corax | American Robin Turdus migratorius | 2 | 2 | 0 |
| Canada Goose Branta canadensis | Sandhill Crane Antigone canadensis | 1 | 0 | 1 |
| Whooper Swan Cygnus cygnus | Muscovy Duck Cairina moschata | 1 | 0 | 1 |
| Wood Duck Aix sponsa | Hooded Merganser Lophodytes cucullatus | 1 | 0 | 1 |
| Redhead Aythya americana | Greater Scaup Aythya marila | 1 | 1 | 0 |
| Lesser Scaup Aythya affinis | Common Eider Somateria mollissima | 1 | 0 | 1 |
| Lesser Scaup Aythya affinis | Black-throated Green Warbler Setophaga virens | 1 | 0 | 1 |
| Surf Scoter Melanitta perspicillata | Black Scoter Melanitta americana | 1 | 0 | 1 |
| White-winged Scoter Melanitta deglandi | Black Scoter Melanitta americana | 1 | 0 | 1 |
| White-winged Scoter Melanitta deglandi | Stilt Sandpiper Calidris himantopus | 1 | 1 | 0 |
| Black Scoter Melanitta americana | Long-tailed Duck Clangula hyemalis | 1 | 0 | 1 |
| Bufflehead Bucephala albeola | Hooded Merganser Lophodytes cucullatus | 1 | 1 | 0 |
| Common Goldeneye Bucephala clangula | Goosander Mergus merganser | 1 | 1 | 0 |
| Red-breasted Merganser Mergus serrator | Ruddy Duck Oxyura jamaicensis | 1 | 1 | 0 |
| Red-breasted Merganser Mergus serrator | Sooty Shearwater Ardenna grisea | 1 | 0 | 1 |
| Ruddy Duck Oxyura jamaicensis | Red-necked Phalarope Phalaropus lobatus | 1 | 0 | 1 |
| Northern Bobwhite Colinus virginianus | Black-necked Grebe Podiceps nigricollis | 1 | 0 | 1 |
| Northern Bobwhite Colinus virginianus | Western Meadowlark Sturnella neglecta | 1 | 1 | 0 |
| Red-necked Grebe Podiceps grisegena | Townsend's Solitaire Myadestes townsendi | 1 | 0 | 1 |
| Western Grebe Aechmophorus occidentalis | Eastern Phoebe Sayornis phoebe | 1 | 0 | 1 |
| Western Grebe Aechmophorus occidentalis | Golden-crowned Sparrow Zonotrichia atricapilla | 1 | 0 | 1 |
| Band-tailed Pigeon Patagioenas fasciata | Mourning Dove Zenaida macroura | 1 | 1 | 0 |
| Mourning Dove Zenaida macroura | Clay-coloured Sparrow Spizella pallida | 1 | 1 | 0 |
| Common Nighthawk Chordeiles minor | Chuck-will's-widow Antrostomus carolinensis | 1 | 0 | 1 |
| Common Nighthawk Chordeiles minor | Eastern Whip-poor-will Antrostomus vociferus | 1 | 0 | 1 |
| Black-chinned Hummingbird Archilochus alexandri | Rufous Hummingbird Selasphorus rufus | 1 | 0 | 1 |
| Clapper Rail Rallus crepitans | Sora Porzana carolina | 1 | 0 | 1 |
| Sandhill Crane Antigone canadensis | Snow Bunting Plectrophenax nivalis | 1 | 1 | 0 |
| Black-necked Stilt Himantopus mexicanus | American Avocet Recurvirostra americana | 1 | 0 | 1 |
| American Golden Plover Pluvialis dominica | Pacific Golden Plover Pluvialis fulva | 1 | 0 | 1 |
| Killdeer Charadrius vociferus | Semipalmated Plover Charadrius semipalmatus | 1 | 1 | 0 |
| Eskimo Curlew Numenius borealis | Long-billed Curlew Numenius americanus | 1 | 1 | 0 |
| Eskimo Curlew Numenius borealis | Pacific Diver Gavia pacifica | 1 | 0 | 1 |
| Black-tailed Godwit Limosa limosa | Hudsonian Godwit Limosa haemastica | 1 | 1 | 0 |
| Hudsonian Godwit Limosa haemastica | Wilson's Phalarope Phalaropus tricolor | 1 | 1 | 0 |
| Marbled Godwit Limosa fedoa | Wilson's Snipe Gallinago delicata | 1 | 1 | 0 |
| American Woodcock Scolopax minor | White-rumped Sandpiper Calidris fuscicollis | 1 | 0 | 1 |
| American Woodcock Scolopax minor | Least Flycatcher Empidonax minimus | 1 | 1 | 0 |
| Grey Phalarope Phalaropus fulicarius | Red-necked Phalarope Phalaropus lobatus | 1 | 1 | 0 |
| Lesser Yellowlegs Tringa flavipes | Greater Yellowlegs Tringa melanoleuca | 1 | 1 | 0 |
| Willet Tringa semipalmata | Greater Yellowlegs Tringa melanoleuca | 1 | 1 | 0 |
| Willet Tringa semipalmata | Ruff Calidris pugnax | 1 | 1 | 0 |
| Ruddy Turnstone Arenaria interpres | Ruff Calidris pugnax | 1 | 0 | 1 |
| Ruddy Turnstone Arenaria interpres | Arctic Skua Stercorarius parasiticus | 1 | 0 | 1 |
| Ruff Calidris pugnax | Great Shearwater Ardenna gravis | 1 | 1 | 0 |
| Sanderling Calidris alba | Purple Sandpiper Calidris maritima | 1 | 0 | 1 |
| Sanderling Calidris alba | Baird's Sandpiper Calidris bairdii | 1 | 0 | 1 |
| Western Sandpiper Calidris mauri | Savannah Sparrow Passerculus sandwichensis | 1 | 0 | 1 |
| Long-tailed Skua Stercorarius longicaudus | Yellow-bellied Sapsucker Sphyrapicus varius | 1 | 0 | 1 |
| Pomarine Skua Stercorarius pomarinus | South Polar Skua Stercorarius maccormicki | 1 | 1 | 0 |
| Black Guillemot Cepphus grylle | Common Guillemot Uria aalge | 1 | 0 | 1 |
| Brünnich's Guillemot Uria lomvia | Black Tern Chlidonias niger | 1 | 0 | 1 |
| Little Gull Hydrocoloeus minutus | Ivory Gull Pagophila eburnea | 1 | 0 | 1 |
| Ivory Gull Pagophila eburnea | Sabine's Gull Xema sabini | 1 | 1 | 0 |
| Sabine's Gull Xema sabini | Franklin's Gull Leucophaeus pipixcan | 1 | 1 | 0 |
| Bonaparte's Gull Chroicocephalus philadelphia | Black-headed Gull Chroicocephalus ridibundus | 1 | 1 | 0 |
| Bonaparte's Gull Chroicocephalus philadelphia | Laughing Gull Leucophaeus atricilla | 1 | 0 | 1 |
| Bonaparte's Gull Chroicocephalus philadelphia | Franklin's Gull Leucophaeus pipixcan | 1 | 0 | 1 |
| Ring-billed Gull Larus delawarensis | Glaucous Gull Larus hyperboreus | 1 | 0 | 1 |
| Ring-billed Gull Larus delawarensis | California Gull Larus californicus | 1 | 1 | 0 |
| Glaucous Gull Larus hyperboreus | Iceland Gull Larus glaucoides | 1 | 0 | 1 |
| Forster's Tern Sterna forsteri | Arctic Tern Sterna paradisaea | 1 | 0 | 1 |
| Forster's Tern Sterna forsteri | Common Tern Sterna hirundo | 1 | 1 | 0 |
| Arctic Tern Sterna paradisaea | Common Tern Sterna hirundo | 1 | 1 | 0 |
| Pacific Diver Gavia pacifica | Great Northern Diver Gavia immer | 1 | 1 | 0 |
| Wilson's Storm-Petrel Oceanites oceanicus | Leach's Storm-Petrel Hydrobates leucorhous | 1 | 1 | 0 |
| European Storm-Petrel Hydrobates pelagicus | Great Shearwater Ardenna gravis | 1 | 0 | 1 |
| American White Pelican Pelecanus erythrorhynchos | Blackburnian Warbler Setophaga fusca | 1 | 1 | 0 |
| Turkey Vulture Cathartes aura | Golden Eagle Aquila chrysaetos | 1 | 1 | 0 |
| Golden Eagle Aquila chrysaetos | Mississippi Kite Ictinia mississippiensis | 1 | 0 | 1 |
| Mississippi Kite Ictinia mississippiensis | Sharp-shinned Hawk Accipiter striatus | 1 | 0 | 1 |
| Bald Eagle Haliaeetus leucocephalus | Broad-winged Hawk Buteo platypterus | 1 | 0 | 1 |
| Red-tailed Hawk Buteo jamaicensis | Rough-legged Buzzard Buteo lagopus | 1 | 1 | 0 |
| Yellow-bellied Sapsucker Sphyrapicus varius | Northern Flicker Colaptes auratus | 1 | 0 | 1 |
| Black-backed Woodpecker Picoides arcticus | Yellow-headed Blackbird Xanthocephalus xanthocephalus | 1 | 0 | 1 |
| Downy Woodpecker Dryobates pubescens | Hairy Woodpecker Leuconotopicus villosus | 1 | 1 | 0 |
| Crested Caracara Caracara plancus | Gyr Falcon Falco rusticolus | 1 | 0 | 1 |
| American Kestrel Falco sparverius | Peregrine Falcon Falco peregrinus | 1 | 0 | 1 |
| Merlin Falco columbarius | Peregrine Falcon Falco peregrinus | 1 | 0 | 1 |
| Eastern Wood-Pewee Contopus virens | Alder Flycatcher Empidonax alnorum | 1 | 0 | 1 |
| Eastern Wood-Pewee Contopus virens | Least Flycatcher Empidonax minimus | 1 | 0 | 1 |
| Yellow-bellied Flycatcher Empidonax flaviventris | Alder Flycatcher Empidonax alnorum | 1 | 0 | 1 |
| Yellow-bellied Flycatcher Empidonax flaviventris | Lincoln's Sparrow Melospiza lincolnii | 1 | 1 | 0 |
| Alder Flycatcher Empidonax alnorum | Least Flycatcher Empidonax minimus | 1 | 0 | 1 |
| Alder Flycatcher Empidonax alnorum | Vesper Sparrow Pooecetes gramineus | 1 | 0 | 1 |
| Hammond's Flycatcher Empidonax hammondii | Clay-coloured Sparrow Spizella pallida | 1 | 1 | 0 |
| Western Flycatcher Empidonax difficilis | Western Kingbird Tyrannus verticalis | 1 | 0 | 1 |
| Say's Phoebe Sayornis saya | Northern Rough-winged Swallow Stelgidopteryx serripennis | 1 | 1 | 0 |
| Great Crested Flycatcher Myiarchus crinitus | Western Kingbird Tyrannus verticalis | 1 | 1 | 0 |
| Bell's Vireo Vireo bellii | Tennessee Warbler Leiothlypis peregrina | 1 | 1 | 0 |
| Philadelphia Vireo Vireo philadelphicus | Northern Shrike Lanius borealis | 1 | 0 | 1 |
| Loggerhead Shrike Lanius ludovicianus | Canada Jay Perisoreus canadensis | 1 | 1 | 0 |
| Canada Jay Perisoreus canadensis | Common Raven Corvus corax | 1 | 1 | 0 |
| Canada Jay Perisoreus canadensis | American Robin Turdus migratorius | 1 | 1 | 0 |
| Canada Jay Perisoreus canadensis | Ovenbird Seiurus aurocapilla | 1 | 0 | 1 |
| Black-billed Magpie Pica hudsonia | Black-capped Chickadee Poecile atricapillus | 1 | 1 | 0 |
| American Crow Corvus brachyrhynchos | Common Raven Corvus corax | 1 | 1 | 0 |
| Shore Lark Eremophila alpestris | Black-throated Grey Warbler Setophaga nigrescens | 1 | 1 | 0 |
| Tree Swallow Tachycineta bicolor | Purple Martin Progne subis | 1 | 1 | 0 |
| Tree Swallow Tachycineta bicolor | Cliff Swallow Petrochelidon pyrrhonota | 1 | 1 | 0 |
| Purple Martin Progne subis | Barn Swallow Hirundo rustica | 1 | 1 | 0 |
| Northern Rough-winged Swallow Stelgidopteryx serripennis | Barn Swallow Hirundo rustica | 1 | 0 | 1 |
| Northern Rough-winged Swallow Stelgidopteryx serripennis | White-crowned Sparrow Zonotrichia leucophrys | 1 | 0 | 1 |
| Cliff Swallow Petrochelidon pyrrhonota | Cave Swallow Petrochelidon fulva | 1 | 1 | 0 |
| Golden-crowned Kinglet Regulus satrapa | Lincoln's Sparrow Melospiza lincolnii | 1 | 0 | 1 |
| White-breasted Nuthatch Sitta carolinensis | Brown Creeper Certhia americana | 1 | 0 | 1 |
| Brown Creeper Certhia americana | Wood Thrush Hylocichla mustelina | 1 | 1 | 0 |
| Sedge Wren Cistothorus stellaris | Seaside Sparrow Ammospiza maritima | 1 | 0 | 1 |
| Brown Thrasher Toxostoma rufum | Townsend's Warbler Setophaga townsendi | 1 | 1 | 0 |
| Eastern Bluebird Sialia sialis | Mountain Bluebird Sialia currucoides | 1 | 0 | 1 |
| Eastern Bluebird Sialia sialis | Bay-breasted Warbler Setophaga castanea | 1 | 1 | 0 |
| Mountain Bluebird Sialia currucoides | Townsend's Solitaire Myadestes townsendi | 1 | 1 | 0 |
| Townsend's Solitaire Myadestes townsendi | Buff-bellied Pipit Anthus rubescens | 1 | 0 | 1 |
| Varied Thrush Ixoreus naevius | Lincoln's Sparrow Melospiza lincolnii | 1 | 0 | 1 |
| Veery Catharus fuscescens | Grey-cheeked Thrush Catharus minimus | 1 | 1 | 0 |
| Grey-cheeked Thrush Catharus minimus | LeConte's Sparrow Ammospiza leconteii | 1 | 0 | 1 |
| Swainson's Thrush Catharus ustulatus | Wood Thrush Hylocichla mustelina | 1 | 1 | 0 |
| Swainson's Thrush Catharus ustulatus | Chipping Sparrow Spizella passerina | 1 | 1 | 0 |
| Bohemian Waxwing Bombycilla garrulus | Cedar Waxwing Bombycilla cedrorum | 1 | 1 | 0 |
| Chipping Sparrow Spizella passerina | Clay-coloured Sparrow Spizella pallida | 1 | 0 | 1 |
| Chipping Sparrow Spizella passerina | American Tree Sparrow Spizelloides arborea | 1 | 1 | 0 |
| Clay-coloured Sparrow Spizella pallida | Lark Sparrow Chondestes grammacus | 1 | 1 | 0 |
| Brewer's Sparrow Spizella breweri | Lark Sparrow Chondestes grammacus | 1 | 1 | 0 |
| Lark Sparrow Chondestes grammacus | Lark Bunting Calamospiza melanocorys | 1 | 0 | 1 |
| Lark Bunting Calamospiza melanocorys | American Tree Sparrow Spizelloides arborea | 1 | 1 | 0 |
| American Tree Sparrow Spizelloides arborea | White-crowned Sparrow Zonotrichia leucophrys | 1 | 1 | 0 |
| LeConte's Sparrow Ammospiza leconteii | Savannah Sparrow Passerculus sandwichensis | 1 | 0 | 1 |
| Nelson's Sparrow Ammospiza nelsoni | Savannah Sparrow Passerculus sandwichensis | 1 | 0 | 1 |
| Western Meadowlark Sturnella neglecta | Eastern Meadowlark Sturnella magna | 1 | 0 | 1 |
| Red-winged Blackbird Agelaius phoeniceus | Rusty Blackbird Euphagus carolinus | 1 | 0 | 1 |
| Brown-headed Cowbird Molothrus ater | Rusty Blackbird Euphagus carolinus | 1 | 0 | 1 |
| Brown-headed Cowbird Molothrus ater | Brewer's Blackbird Euphagus cyanocephalus | 1 | 1 | 0 |
| Northern Waterthrush Parkesia noveboracensis | Palm Warbler Setophaga palmarum | 1 | 0 | 1 |
| Black-and-white Warbler Mniotilta varia | Blackpoll Warbler Setophaga striata | 1 | 1 | 0 |
| Orange-crowned Warbler Leiothlypis celata | Nashville Warbler Leiothlypis ruficapilla | 1 | 1 | 0 |
| Orange-crowned Warbler Leiothlypis celata | Western Tanager Piranga ludoviciana | 1 | 0 | 1 |
| Nashville Warbler Leiothlypis ruficapilla | Yellow-rumped Warbler Setophaga coronata | 1 | 1 | 0 |
| Connecticut Warbler Oporornis agilis | Mourning Warbler Geothlypis philadelphia | 1 | 1 | 0 |
| Connecticut Warbler Oporornis agilis | Common Yellowthroat Geothlypis trichas | 1 | 0 | 1 |
| Cape May Warbler Setophaga tigrina | Magnolia Warbler Setophaga magnolia | 1 | 1 | 0 |
| Cape May Warbler Setophaga tigrina | Bay-breasted Warbler Setophaga castanea | 1 | 1 | 0 |
| Northern Parula Setophaga americana | Magnolia Warbler Setophaga magnolia | 1 | 0 | 1 |
| Bay-breasted Warbler Setophaga castanea | Chestnut-sided Warbler Setophaga pensylvanica | 1 | 1 | 0 |
| Blackpoll Warbler Setophaga striata | Black-throated Blue Warbler Setophaga caerulescens | 1 | 0 | 1 |
| Townsend's Warbler Setophaga townsendi | Canada Warbler Cardellina canadensis | 1 | 1 | 0 |
| Hermit Warbler Setophaga occidentalis | Black-throated Green Warbler Setophaga virens | 1 | 1 | 0 |
| Hermit Warbler Setophaga occidentalis | Wilson's Warbler Cardellina pusilla | 1 | 0 | 1 |
| Rose-breasted Grosbeak Pheucticus ludovicianus | Blue Grosbeak Passerina caerulea | 1 | 1 | 0 |
| Cory's Shearwater Calonectris borealis | Scopoli's Shearwater Calonectris diomedea | 1 | 1 | 0 |
| Snow Goose Anser caerulescens | Greater White-fronted Goose Anser albifrons | 1 | 1 | 0 |
| Snow Goose Anser caerulescens | Common Raven Corvus corax | 1 | 0 | 1 |
| Snow Goose Anser caerulescens | American Robin Turdus migratorius | 1 | 1 | 0 |
| Snow Goose Anser caerulescens | Snow Bunting Plectrophenax nivalis | 1 | 0 | 1 |
| Greater White-fronted Goose Anser albifrons | Brent Goose Branta bernicla | 1 | 0 | 1 |
| Greater White-fronted Goose Anser albifrons | California Gull Larus californicus | 1 | 0 | 1 |
| Greater White-fronted Goose Anser albifrons | Canada Jay Perisoreus canadensis | 1 | 1 | 0 |
| Brent Goose Branta bernicla | Red-necked Grebe Podiceps grisegena | 1 | 0 | 1 |
| Brent Goose Branta bernicla | Glaucous Gull Larus hyperboreus | 1 | 1 | 0 |