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 |
|---|---|---|---|---|
| Black-bellied Whistling-Duck Dendrocygna autumnalis | Fulvous Whistling-Duck Dendrocygna bicolor | 4 | 2 | 2 |
| Common Goldeneye Bucephala clangula | Barrow's Goldeneye Bucephala islandica | 4 | 3 | 1 |
| Western Flycatcher Empidonax difficilis | Vermilion Flycatcher Pyrocephalus rubinus | 3 | 3 | 0 |
| Black-necked Grebe Podiceps nigricollis | Western Grebe Aechmophorus occidentalis | 3 | 2 | 1 |
| Ruddy Turnstone Arenaria interpres | Red Knot Calidris canutus | 3 | 1 | 2 |
| Common Tern Sterna hirundo | Royal Tern Thalasseus maximus | 3 | 3 | 0 |
| Buff-bellied Pipit Anthus rubescens | Sprague's Pipit Anthus spragueii | 2 | 0 | 2 |
| Canvasback Aythya valisineria | Redhead Aythya americana | 2 | 2 | 0 |
| Black-headed Grosbeak Pheucticus melanocephalus | Lazuli Bunting Passerina amoena | 2 | 1 | 1 |
| White-winged Scoter Melanitta deglandi | Black Scoter Melanitta americana | 2 | 1 | 1 |
| Allen's Hummingbird Selasphorus sasin | Broad-billed Hummingbird Cynanthus latirostris | 2 | 1 | 1 |
| Snow Goose Anser caerulescens | Ross's Goose Anser rossii | 2 | 0 | 2 |
| Vesper Sparrow Pooecetes gramineus | LeConte's Sparrow Ammospiza leconteii | 2 | 1 | 1 |
| Bewick's Swan Cygnus columbianus | Whooper Swan Cygnus cygnus | 2 | 0 | 2 |
| Common Eider Somateria mollissima | Surf Scoter Melanitta perspicillata | 2 | 1 | 1 |
| Ring-necked Duck Aythya collaris | White-rumped Sandpiper Calidris fuscicollis | 1 | 1 | 0 |
| Greater Scaup Aythya marila | Lesser Scaup Aythya affinis | 1 | 0 | 1 |
| King Eider Somateria spectabilis | Common Eider Somateria mollissima | 1 | 0 | 1 |
| King Eider Somateria spectabilis | Harlequin Duck Histrionicus histrionicus | 1 | 0 | 1 |
| King Eider Somateria spectabilis | Cape May Warbler Setophaga tigrina | 1 | 1 | 0 |
| King Eider Somateria spectabilis | Lazuli Bunting Passerina amoena | 1 | 1 | 0 |
| Surf Scoter Melanitta perspicillata | Black Scoter Melanitta americana | 1 | 0 | 1 |
| Surf Scoter Melanitta perspicillata | American Golden Plover Pluvialis dominica | 1 | 0 | 1 |
| Black Scoter Melanitta americana | Bufflehead Bucephala albeola | 1 | 0 | 1 |
| Bufflehead Bucephala albeola | Barrow's Goldeneye Bucephala islandica | 1 | 0 | 1 |
| Common Goldeneye Bucephala clangula | Crested Caracara Caracara plancus | 1 | 1 | 0 |
| Barrow's Goldeneye Bucephala islandica | Ruddy Duck Oxyura jamaicensis | 1 | 0 | 1 |
| Goosander Mergus merganser | Red-breasted Merganser Mergus serrator | 1 | 0 | 1 |
| Goosander Mergus merganser | Grey-cheeked Thrush Catharus minimus | 1 | 1 | 0 |
| Northern Bobwhite Colinus virginianus | Golden Pheasant Chrysolophus pictus | 1 | 1 | 0 |
| Ruffed Grouse Bonasa umbellus | Red-legged Partridge Alectoris rufa | 1 | 0 | 1 |
| Golden Pheasant Chrysolophus pictus | Roseate Tern Sterna dougallii | 1 | 1 | 0 |
| Red-legged Partridge Alectoris rufa | Western Grebe Aechmophorus occidentalis | 1 | 0 | 1 |
| White-winged Dove Zenaida asiatica | Mourning Dove Zenaida macroura | 1 | 0 | 1 |
| Groove-billed Ani Crotophaga sulcirostris | American Moorhen Gallinula galeata | 1 | 0 | 1 |
| Black-billed Cuckoo Coccyzus erythropthalmus | Scissor-tailed Flycatcher Tyrannus forficatus | 1 | 0 | 1 |
| Eastern Whip-poor-will Antrostomus vociferus | Painted Bunting Passerina ciris | 1 | 0 | 1 |
| Mexican Violetear Colibri thalassinus | Black-chinned Hummingbird Archilochus alexandri | 1 | 1 | 0 |
| Mexican Violetear Colibri thalassinus | White-faced Ibis Plegadis chihi | 1 | 0 | 1 |
| Black-chinned Hummingbird Archilochus alexandri | Calliope Hummingbird Selasphorus calliope | 1 | 0 | 1 |
| Rufous Hummingbird Selasphorus rufus | Broad-billed Hummingbird Cynanthus latirostris | 1 | 0 | 1 |
| American Moorhen Gallinula galeata | American Coot Fulica americana | 1 | 0 | 1 |
| American Moorhen Gallinula galeata | Two-barred Crossbill Loxia leucoptera | 1 | 1 | 0 |
| Sandhill Crane Antigone canadensis | Red-winged Blackbird Agelaius phoeniceus | 1 | 0 | 1 |
| American Avocet Recurvirostra americana | Eastern Wood-Pewee Contopus virens | 1 | 1 | 0 |
| Grey Plover Pluvialis squatarola | Northern Lapwing Vanellus vanellus | 1 | 0 | 1 |
| Grey Plover Pluvialis squatarola | Wilson's Plover Anarhynchus wilsonia | 1 | 1 | 0 |
| Semipalmated Plover Charadrius semipalmatus | Anhinga Anhinga anhinga | 1 | 0 | 1 |
| Short-billed Dowitcher Limnodromus griseus | Long-billed Dowitcher Limnodromus scolopaceus | 1 | 1 | 0 |
| Grey Phalarope Phalaropus fulicarius | White-faced Ibis Plegadis chihi | 1 | 0 | 1 |
| Willet Tringa semipalmata | Semipalmated Sandpiper Calidris pusilla | 1 | 1 | 0 |
| Ruddy Turnstone Arenaria interpres | Short-billed Gull Larus brachyrhynchus | 1 | 1 | 0 |
| Ruddy Turnstone Arenaria interpres | Western Flycatcher Empidonax difficilis | 1 | 1 | 0 |
| White-rumped Sandpiper Calidris fuscicollis | Turkey Vulture Cathartes aura | 1 | 0 | 1 |
| Western Sandpiper Calidris mauri | Arctic Skua Stercorarius parasiticus | 1 | 0 | 1 |
| Long-tailed Skua Stercorarius longicaudus | Great Black-backed Gull Larus marinus | 1 | 1 | 0 |
| Arctic Skua Stercorarius parasiticus | Ancient Murrelet Synthliboramphus antiquus | 1 | 0 | 1 |
| Pomarine Skua Stercorarius pomarinus | Northern Parula Setophaga americana | 1 | 0 | 1 |
| Black Guillemot Cepphus grylle | Brünnich's Guillemot Uria lomvia | 1 | 1 | 0 |
| Brünnich's Guillemot Uria lomvia | Mourning Warbler Geothlypis philadelphia | 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 | 1 | 0 |
| Black-tailed Gull Larus crassirostris | Heermann's Gull Larus heermanni | 1 | 0 | 1 |
| Common Gull Larus canus | Short-billed Gull Larus brachyrhynchus | 1 | 1 | 0 |
| Short-billed Gull Larus brachyrhynchus | Ring-billed Gull Larus delawarensis | 1 | 0 | 1 |
| Ring-billed Gull Larus delawarensis | White-eyed Vireo Vireo griseus | 1 | 1 | 0 |
| Caspian Tern Hydroprogne caspia | Black Tern Chlidonias niger | 1 | 0 | 1 |
| Forster's Tern Sterna forsteri | Arctic Tern Sterna paradisaea | 1 | 0 | 1 |
| Arctic Tern Sterna paradisaea | White-eyed Vireo Vireo griseus | 1 | 0 | 1 |
| Common Tern Sterna hirundo | Ovenbird Seiurus aurocapilla | 1 | 0 | 1 |
| Red-throated Diver Gavia stellata | Black-throated Diver Gavia arctica | 1 | 1 | 0 |
| Black-capped Petrel Pterodroma hasitata | Hooded Oriole Icterus cucullatus | 1 | 0 | 1 |
| Magnificent Frigatebird Fregata magnificens | Swamp Sparrow Melospiza georgiana | 1 | 0 | 1 |
| Northern Gannet Morus bassanus | Loggerhead Shrike Lanius ludovicianus | 1 | 1 | 0 |
| Brown Booby Sula leucogaster | Double-crested Cormorant Nannopterum auritum | 1 | 1 | 0 |
| Great Cormorant Phalacrocorax carbo | Double-crested Cormorant Nannopterum auritum | 1 | 1 | 0 |
| Double-crested Cormorant Nannopterum auritum | Neotropic Cormorant Nannopterum brasilianum | 1 | 0 | 1 |
| Yellow-crowned Night Heron Nyctanassa violacea | Tricoloured Heron Egretta tricolor | 1 | 1 | 0 |
| Black-crowned Night Heron Nycticorax nycticorax | Tricoloured Heron Egretta tricolor | 1 | 1 | 0 |
| Black-crowned Night Heron Nycticorax nycticorax | Black-throated Blue Warbler Setophaga caerulescens | 1 | 1 | 0 |
| Green Heron Butorides virescens | Great Blue Heron Ardea herodias | 1 | 0 | 1 |
| Osprey Pandion haliaetus | Northern Harrier Circus hudsonius | 1 | 1 | 0 |
| White-tailed Kite Elanus leucurus | Sharp-shinned Hawk Accipiter striatus | 1 | 1 | 0 |
| Mississippi Kite Ictinia mississippiensis | Sharp-shinned Hawk Accipiter striatus | 1 | 0 | 1 |
| Northern Harrier Circus hudsonius | Sharp-shinned Hawk Accipiter striatus | 1 | 0 | 1 |
| Sharp-shinned Hawk Accipiter striatus | Cooper's Hawk Astur cooperii | 1 | 0 | 1 |
| Cooper's Hawk Astur cooperii | American Goshawk Astur atricapillus | 1 | 0 | 1 |
| Red-tailed Hawk Buteo jamaicensis | Ferruginous Hawk Buteo regalis | 1 | 1 | 0 |
| Eastern Screech-Owl Megascops asio | Burrowing Owl Athene cunicularia | 1 | 1 | 0 |
| Great Horned Owl Bubo virginianus | Northern Hawk Owl Surnia ulula | 1 | 1 | 0 |
| Yellow-bellied Sapsucker Sphyrapicus varius | Red-cockaded Woodpecker Leuconotopicus borealis | 1 | 1 | 0 |
| Eastern Wood-Pewee Contopus virens | Veery Catharus fuscescens | 1 | 0 | 1 |
| Eastern Wood-Pewee Contopus virens | Pine Warbler Setophaga pinus | 1 | 1 | 0 |
| Alder Flycatcher Empidonax alnorum | Least Flycatcher Empidonax minimus | 1 | 1 | 0 |
| Willow Flycatcher Empidonax traillii | Grey Flycatcher Empidonax wrightii | 1 | 0 | 1 |
| Grey Flycatcher Empidonax wrightii | Dusky Flycatcher Empidonax oberholseri | 1 | 0 | 1 |
| Grey Flycatcher Empidonax wrightii | Eastern Phoebe Sayornis phoebe | 1 | 1 | 0 |
| Eastern Phoebe Sayornis phoebe | Brewer's Sparrow Spizella breweri | 1 | 0 | 1 |
| Western Kingbird Tyrannus verticalis | Prairie Warbler Setophaga discolor | 1 | 1 | 0 |
| White-eyed Vireo Vireo griseus | Ruby-crowned Kinglet Corthylio calendula | 1 | 0 | 1 |
| Bell's Vireo Vireo bellii | Snow Bunting Plectrophenax nivalis | 1 | 0 | 1 |
| Yellow-throated Vireo Vireo flavifrons | Philadelphia Vireo Vireo philadelphicus | 1 | 0 | 1 |
| Blue-headed Vireo Vireo solitarius | Mountain Bluebird Sialia currucoides | 1 | 0 | 1 |
| Philadelphia Vireo Vireo philadelphicus | Tennessee Warbler Leiothlypis peregrina | 1 | 1 | 0 |
| Loggerhead Shrike Lanius ludovicianus | Louisiana Waterthrush Parkesia motacilla | 1 | 0 | 1 |
| Azure-winged Magpie Cyanopica cyanus | Black-billed Magpie Pica hudsonia | 1 | 1 | 0 |
| Azure-winged Magpie Cyanopica cyanus | American Crow Corvus brachyrhynchos | 1 | 1 | 0 |
| Azure-winged Magpie Cyanopica cyanus | Bullock's Oriole Icterus bullockii | 1 | 0 | 1 |
| Carolina Chickadee Poecile carolinensis | Barn Swallow Hirundo rustica | 1 | 1 | 0 |
| Carolina Chickadee Poecile carolinensis | Varied Thrush Ixoreus naevius | 1 | 0 | 1 |
| Tufted Titmouse Baeolophus bicolor | Northern Cardinal Cardinalis cardinalis | 1 | 0 | 1 |
| Shore Lark Eremophila alpestris | Cliff Swallow Petrochelidon pyrrhonota | 1 | 0 | 1 |
| Shore Lark Eremophila alpestris | White-crowned Sparrow Zonotrichia leucophrys | 1 | 1 | 0 |
| Sand Martin Riparia riparia | Tree Swallow Tachycineta bicolor | 1 | 0 | 1 |
| Purple Martin Progne subis | Barn Swallow Hirundo rustica | 1 | 1 | 0 |
| Purple Martin Progne subis | Brewer's Blackbird Euphagus cyanocephalus | 1 | 0 | 1 |
| Cliff Swallow Petrochelidon pyrrhonota | Cave Swallow Petrochelidon fulva | 1 | 1 | 0 |
| Ruby-crowned Kinglet Corthylio calendula | Northern Mockingbird Mimus polyglottos | 1 | 1 | 0 |
| Golden-crowned Kinglet Regulus satrapa | Brown-headed Nuthatch Sitta pusilla | 1 | 1 | 0 |
| Golden-crowned Kinglet Regulus satrapa | Northern Parula Setophaga americana | 1 | 0 | 1 |
| Brown-headed Nuthatch Sitta pusilla | Brown Creeper Certhia americana | 1 | 0 | 1 |
| Brown Creeper Certhia americana | Henslow's Sparrow Centronyx henslowii | 1 | 0 | 1 |
| Blue-grey Gnatcatcher Polioptila caerulea | Black-throated Grey Warbler Setophaga nigrescens | 1 | 0 | 1 |
| Northern House Wren Troglodytes aedon | Carolina Wren Thryothorus ludovicianus | 1 | 0 | 1 |
| Marsh Wren Cistothorus palustris | Bewick's Wren Thryomanes bewickii | 1 | 1 | 0 |
| Bewick's Wren Thryomanes bewickii | Hooded Oriole Icterus cucullatus | 1 | 1 | 0 |
| Townsend's Solitaire Myadestes townsendi | Grey-cheeked Thrush Catharus minimus | 1 | 1 | 0 |
| Grey-cheeked Thrush Catharus minimus | Wood Thrush Hylocichla mustelina | 1 | 1 | 0 |
| Cedar Waxwing Bombycilla cedrorum | Sprague's Pipit Anthus spragueii | 1 | 0 | 1 |
| Pine Grosbeak Pinicola enucleator | Purple Finch Haemorhous purpureus | 1 | 1 | 0 |
| Pine Grosbeak Pinicola enucleator | Vesper Sparrow Pooecetes gramineus | 1 | 0 | 1 |
| House Finch Haemorhous mexicanus | Common Crossbill Loxia curvirostra | 1 | 1 | 0 |
| European Greenfinch Chloris chloris | Blackpoll Warbler Setophaga striata | 1 | 1 | 0 |
| Atlantic Canary Serinus canaria | LeConte's Sparrow Ammospiza leconteii | 1 | 0 | 1 |
| Atlantic Canary Serinus canaria | Nelson's Sparrow Ammospiza nelsoni | 1 | 1 | 0 |
| Pine Siskin Spinus pinus | Lapland Bunting Calcarius lapponicus | 1 | 0 | 1 |
| American Goldfinch Spinus tristis | Redpoll Acanthis flammea | 1 | 1 | 0 |
| Grasshopper Sparrow Ammodramus savannarum | Bay-breasted Warbler Setophaga castanea | 1 | 1 | 0 |
| Chipping Sparrow Spizella passerina | Field Sparrow Spizella pusilla | 1 | 1 | 0 |
| Clay-coloured Sparrow Spizella pallida | Field Sparrow Spizella pusilla | 1 | 0 | 1 |
| Field Sparrow Spizella pusilla | Lark Sparrow Chondestes grammacus | 1 | 1 | 0 |
| Lark Sparrow Chondestes grammacus | American Tree Sparrow Spizelloides arborea | 1 | 1 | 0 |
| Lark Sparrow Chondestes grammacus | Blackpoll Warbler Setophaga striata | 1 | 0 | 1 |
| American Tree Sparrow Spizelloides arborea | Dark-eyed Junco Junco hyemalis | 1 | 0 | 1 |
| White-crowned Sparrow Zonotrichia leucophrys | Western Meadowlark Sturnella neglecta | 1 | 0 | 1 |
| Harris's Sparrow Zonotrichia querula | Vesper Sparrow Pooecetes gramineus | 1 | 1 | 0 |
| Savannah Sparrow Passerculus sandwichensis | Henslow's Sparrow Centronyx henslowii | 1 | 0 | 1 |
| Savannah Sparrow Passerculus sandwichensis | Song Sparrow Melospiza melodia | 1 | 1 | 0 |
| Savannah Sparrow Passerculus sandwichensis | Green-tailed Towhee Pipilo chlorurus | 1 | 0 | 1 |
| Swamp Sparrow Melospiza georgiana | Cerulean Warbler Setophaga cerulea | 1 | 0 | 1 |
| Orchard Oriole Icterus spurius | Bullock's Oriole Icterus bullockii | 1 | 1 | 0 |
| Bullock's Oriole Icterus bullockii | Baltimore Oriole Icterus galbula | 1 | 0 | 1 |
| Rusty Blackbird Euphagus carolinus | Common Grackle Quiscalus quiscula | 1 | 1 | 0 |
| Orange-crowned Warbler Leiothlypis celata | Nashville Warbler Leiothlypis ruficapilla | 1 | 1 | 0 |
| Orange-crowned Warbler Leiothlypis celata | Mourning Warbler Geothlypis philadelphia | 1 | 1 | 0 |
| Orange-crowned Warbler Leiothlypis celata | Wilson's Warbler Cardellina pusilla | 1 | 1 | 0 |
| Nashville Warbler Leiothlypis ruficapilla | Virginia's Warbler Leiothlypis virginiae | 1 | 0 | 1 |
| Nashville Warbler Leiothlypis ruficapilla | Mourning Warbler Geothlypis philadelphia | 1 | 1 | 0 |
| Virginia's Warbler Leiothlypis virginiae | Mourning Warbler Geothlypis philadelphia | 1 | 1 | 0 |
| Kentucky Warbler Geothlypis formosa | Hooded Warbler Setophaga citrina | 1 | 1 | 0 |
| Northern Parula Setophaga americana | Bay-breasted Warbler Setophaga castanea | 1 | 0 | 1 |
| Chestnut-sided Warbler Setophaga pensylvanica | Palm Warbler Setophaga palmarum | 1 | 1 | 0 |
| Blackpoll Warbler Setophaga striata | Palm Warbler Setophaga palmarum | 1 | 0 | 1 |
| Black-throated Blue Warbler Setophaga caerulescens | Pine Warbler Setophaga pinus | 1 | 0 | 1 |
| Yellow-throated Warbler Setophaga dominica | Black-throated Grey Warbler Setophaga nigrescens | 1 | 0 | 1 |
| Prairie Warbler Setophaga discolor | Black-throated Grey Warbler Setophaga nigrescens | 1 | 0 | 1 |
| Black-throated Grey Warbler Setophaga nigrescens | Townsend's Warbler Setophaga townsendi | 1 | 1 | 0 |
| Black-throated Green Warbler Setophaga virens | Painted Redstart Myioborus pictus | 1 | 1 | 0 |
| Black-throated Green Warbler Setophaga virens | Summer Tanager Piranga rubra | 1 | 1 | 0 |
| Canada Warbler Cardellina canadensis | Wilson's Warbler Cardellina pusilla | 1 | 1 | 0 |
| Summer Tanager Piranga rubra | Scarlet Tanager Piranga olivacea | 1 | 0 | 1 |
| Scarlet Tanager Piranga olivacea | Western Tanager Piranga ludoviciana | 1 | 1 | 0 |
| Blue Grosbeak Passerina caerulea | Lazuli Bunting Passerina amoena | 1 | 1 | 0 |
| Black-bellied Whistling-Duck Dendrocygna autumnalis | Bar-headed Goose Anser indicus | 1 | 1 | 0 |
| Black-bellied Whistling-Duck Dendrocygna autumnalis | Black Tern Chlidonias niger | 1 | 0 | 1 |
| Bar-headed Goose Anser indicus | Snow Goose Anser caerulescens | 1 | 0 | 1 |
| Snow Goose Anser caerulescens | Swan Goose Anser cygnoides | 1 | 1 | 0 |
| Swan Goose Anser cygnoides | Canada Goose Branta canadensis | 1 | 1 | 0 |
| Greater White-fronted Goose Anser albifrons | Common Grackle Quiscalus quiscula | 1 | 1 | 0 |
| Garganey Spatula querquedula | Blue-winged Teal Spatula discors | 1 | 1 | 0 |
| Garganey Spatula querquedula | White-rumped Sandpiper Calidris fuscicollis | 1 | 1 | 0 |
| Cinnamon Teal Spatula cyanoptera | Gadwall Mareca strepera | 1 | 0 | 1 |
| Gadwall Mareca strepera | American Wigeon Mareca americana | 1 | 0 | 1 |
| Falcated Duck Mareca falcata | Eurasian Wigeon Mareca penelope | 1 | 1 | 0 |
| Eurasian Wigeon Mareca penelope | American Wigeon Mareca americana | 1 | 0 | 1 |
| Mallard Anas platyrhynchos | American Black Duck Anas rubripes | 1 | 0 | 1 |
| Ring-necked Duck Aythya collaris | Greater Scaup Aythya marila | 1 | 0 | 1 |