Tocantins Spinetail (undescribed form)
Palawan Cuckoo-Dove (undescribed form)
Chinese x Taiwan Hwamei (hybrid)
Eurasian Moorhen x Eurasian Coot (hybrid)
Hen x Pallid Harrier (hybrid)
Tufted Duck x Greater Scaup (hybrid)
Tricolored x Chestnut Munia (hybrid)
Downy x Nuttall's Woodpecker (hybrid)
Milky x Painted Stork (hybrid)
Common Pochard x Tufted Duck (hybrid)
Ring-necked Duck x Lesser Scaup (hybrid)
Magnolia x Yellow-rumped Warbler (hybrid)
Ferruginous x Tufted Duck (hybrid)
Redhead x Ring-necked Duck (hybrid)
Redhead x scaup sp. (hybrid)
Barnacle x Canada Goose (hybrid)
Chilean x Greater Flamingo (hybrid)
Striated x Green Heron (hybrid)
Common Goldeneye x Hooded Merganser (hybrid)
Black-headed x Mediterranean Gull (hybrid)
African x Gray-headed Swamphen (hybrid)
Snow/Ross's x Cackling/Canada Goose (hybrid)
Wood Duck x Mallard (hybrid)
Anna's x Broad-billed Hummingbird (hybrid)
Common Black x Red-shouldered Hawk (hybrid)
Crimson x Eastern Rosella (hybrid)
White-collared x Golden-collared Manakin (hybrid)
House x Eurasian Tree Sparrow (hybrid)
House x Italian Sparrow (hybrid)
Little Egret x Western Reef-Heron (hybrid)
Pied x Black Stilt (hybrid)
Snow Goose x Brant (hybrid)
Redhead x Lesser Scaup (hybrid)
American Wigeon x Mallard (hybrid)
Cinnamon Teal x Northern Shoveler (hybrid)
Herring x Great Black-backed Gull (hybrid)
Egyptian Goose x Ruddy Shelduck (hybrid)
Northern x Tropical Parula (hybrid)
Yellow-billed Duck x Mallard (hybrid)
Dark-eyed Junco x White-throated Sparrow (hybrid)
Greater White-fronted x Cackling Goose (hybrid)
Rainbow x Red-collared Lorikeet (hybrid)
Eurasian Blue x Azure Tit (hybrid)
Light-vented x Styan's Bulbul (hybrid)
Tufted Duck x Lesser Scaup (hybrid)
Eurasian x African Collared-Dove (hybrid)
Downy x Hairy Woodpecker (hybrid)
Black-capped x Mountain Chickadee (hybrid)
Fischer's x Yellow-collared Lovebird (hybrid)
Cinnamon x Green-winged Teal (hybrid)
Greater White-fronted x Canada Goose (hybrid)
Bar-headed x Canada Goose (hybrid)
Yellow-bellied x Red-naped Sapsucker (hybrid)
Bufflehead x Common Goldeneye (hybrid)
Canvasback x Ring-necked Duck (hybrid)
Blue-winged x Cinnamon Teal (hybrid)
Snow x Ross's Goose (hybrid)
Mexican x Mottled Duck (hybrid)
Muscovy Duck x Mallard (hybrid)
Eurasian x Red-knobbed Coot (hybrid)
Macaroni x Southern Rockhopper Penguin (hybrid)
Common x Barrow's Goldeneye (hybrid)
South Island x Variable Oystercatcher (hybrid)
Domestic goose sp. x Canada Goose (hybrid)
Glaucous x Glaucous-winged Gull (hybrid)
Eurasian x American Wigeon (hybrid)
Gadwall x Mallard (hybrid)
Mallard x Northern Pintail (hybrid)
Tufted Duck x scaup sp. (hybrid)
Spotted x Eastern Towhee (hybrid)
Snow x Greater White-fronted Goose (hybrid)
Ring-necked Duck x scaup sp. (hybrid)
Altamira x Audubon's Oriole (hybrid)
Red-shouldered x Red-tailed Hawk (hybrid)
Carolina x Black-capped Chickadee (hybrid)
Graylag x Swan Goose (hybrid)
Ross's x Cackling Goose (hybrid)
Common Pochard x Ferruginous Duck (hybrid)
Black-throated x Red-throated Thrush (hybrid)
Dusky x Naumann's Thrush (hybrid)
Mallard x Eastern Spot-billed Duck (hybrid)
Graylag x Canada Goose (hybrid)
Snow x Cackling Goose (hybrid)
Herring x Glaucous Gull (hybrid)
Carrion x Hooded Crow (hybrid)
Mallard x Mexican Duck (hybrid)
Swan Goose x Canada Goose (hybrid)
Herring x Glaucous-winged Gull (hybrid)
Red-naped x Red-breasted Sapsucker (hybrid)
Western x Glaucous-winged Gull (hybrid)
American x Black Oystercatcher (hybrid)
Snow x Canada Goose (hybrid)
Mallard x American Black Duck (hybrid)
Mallard x Hawaiian Duck (hybrid)
Ferruginous Duck x Baer's Pochard (hybrid)
White x Scarlet Ibis (hybrid)
Tufted x Black-crested Titmouse (hybrid)
Mallard x Mottled Duck (hybrid)
Mallard x Pacific Black Duck (hybrid)
Eurasian Sparrowhawk/Eurasian Goshawk
Common/Dark-necked Tailorbird
Himalayan/Oriental Cuckoo
Siberian/White-tailed Stonechat
Gray-headed/Eurasian Green Woodpecker
Light-vented/Styan's Bulbul
tanager sp. (Thraupidae sp.)
Bay-breasted/Blackpoll Warbler
Gray-rumped/Ridgetop Swiftlet
Brown/Long-billed Thrasher
Russet-throated/Two-banded Puffbird
Bohemian/Japanese Waxwing
Townsend's/Hermit Warbler
Snowy/Tristan/Antipodean Albatross
Northern/Southern Rough-winged Swallow
Oak/Juniper Titmouse (Plain Titmouse)
Blue-throated/White-throated Piping-Guan
Curve-billed/Bendire's Thrasher
White-barred/White-wedged Piculet
Darjeeling/Crimson-naped Woodpecker
Smooth-billed/Groove-billed Ani
Indian Golden/Black-naped Oriole
Baikal/Spotted Bush Warbler
Common Chaffinch/Brambling
California/Gambel's Quail
Riccordia/Cynanthus/Chlorostilbon sp.
Ashy/Brown-rumped Minivet
Masked/White-browed Woodswallow
Dark-eyed/Yellow-eyed Junco
White-backed Vulture/Cape Griffon
Northern/Southern Royal Albatross
Herring/Glaucous-winged Gull
Bar-tailed/Black-tailed Godwit
Little/Australian Fairy Tern
Red-billed/Yellow-billed Chough
Hammond's/Dusky Flycatcher
Nelson's/Saltmarsh Sparrow (Sharp-tailed Sparrow)
Swinhoe's/Hume's White-eye
Olive-naped/Black-necked Weaver
White-throated/White-browed Fantail
Black-headed/Mediterranean Gull
Red-necked/Eurasian Nightjar
Fulvous/Lesser Whistling-Duck
Red-crowned/Lilac-crowned Parrot
Blunt-winged/Manchurian Reed Warbler
Common/Long-legged Buzzard
Lineated/Brown-headed Barbet
Pale-billed/Nilgiri Flowerpecker
Yellow-billed/Red-billed Blue-Magpie
Rufescent/Gray-breasted Prinia
White-nest/Germain's Swiftlet (Edible-nest Swiftlet)
Black-and-white/Cryptic Becard
Greater/Lesser White-fronted Goose
Yellow-footed/Western Gull
Sulphur-bellied/Tickell's Leaf Warbler
large parakeet sp. (former Aratinga sp.)
Austral/Slender-billed Parakeet
Great Spotted/Syrian Woodpecker
Black-headed/Red-headed Bunting
Mitred/Red-masked Parakeet
White-barred/Ochre-collared Piculet
Eastern/Chihuahuan Meadowlark
Tropical/Northern Mockingbird
American Black/Mottled Duck
Japanese Leaf/Arctic/Kamchatka Leaf Warbler
Black-bellied Plover/golden-plover sp.
elaenia sp. (genus Elaenia)
tanager sp. (Piranga sp.)
Phylloscopus sp. (Golden-spectacled Warbler complex)
Rusty-margined/Social Flycatcher
Greater Short-toed/Hume's Lark
Louisiana/Northern Waterthrush
Warbling/Ticking Doradito
Bassian/Russet-tailed Thrush
Himalayan/Chinese Rubythroat (White-tailed Rubythroat)
Greater/Mongolian Short-toed Lark
Ferruginous Duck/Baer's Pochard
Australasian/Hoary-headed Grebe
Eurasian Moorhen/Common Gallinule
Red-flanked/Himalayan Bluetail
Garganey/Green-winged Teal
Western/Semipalmated Sandpiper
California/Woodhouse's Scrub-Jay
Great Cormorant/European Shag
lovebird sp.
Western/Eastern Cattle Egret
Black-faced/Masked Bunting
storm-petrel sp. (white-rumped)
Western/Eastern Wood-Pewee
Sagebrush/Bell's Sparrow (Sage Sparrow)
Little Egret/Western Reef-Heron
Psittacara sp.
Gray-throated Martin/Bank Swallow
Black-tailed/Green-tailed Trainbearer
eclectus sp.
Sooty/Short-tailed Shearwater
Scaly-breasted/Rainbow Lorikeet
Red-tailed/Isabelline Shrike
Loggerhead/Northern Shrike
Willow Warbler/Common Chiffchaff/Iberian Chiffchaff
Milky/Painted Stork
Blue-throated/Tickell's Blue Flycatcher
White-crested/Straneck's Tyrannulet
Pantanal/Magellanic Snipe
australian treecreeper sp.
Brown-hooded/Gray-hooded Gull
White-rumped/Chilean Swallow
Indian/Indochinese Roller
white-bellied swiftlet sp.
Nuttall's/Ladder-backed Woodpecker
minivet sp. (red minivet sp.)
Parasitic/Pomarine Jaeger
Lesser/Greater Necklaced Laughingthrush
Lesser/Gray-headed Fish-Eagle
Greenish/Two-barred Warbler
Swinhoe's/Indian White-eye
Western/Siberian House-Martin
Russet-naped/Gray-cowled Wood-Rail
Cassin's/Blue-headed Vireo
Himalayan/Eurasian Griffon
Pink-browed/Himalayan White-browed Rosefinch
Jerdon's/Golden-fronted Leafbird
Alder/Willow Flycatcher (Traill's Flycatcher)
Bay-backed/Long-tailed Shrike
Bullock's/Baltimore Oriole
Thick-billed/Common Murre
White-backed Vulture/Rüppell's Griffon
Arctic/Kamchatka Leaf Warbler
Mallard/Pacific Black Duck
Blyth's/Claudia's/Hartert's Leaf Warbler
Chestnut-and-black/Vieillot's Black Weaver
Common/Himalayan/Eastern Buzzard
Boat-tailed/Great-tailed Grackle
Thick-billed/Pale-billed Flowerpecker
Yelkouan/Balearic Shearwater
Malabar/Coppersmith Barbet
Brown-capped/Gray-capped Pygmy Woodpecker
Lesser/Greater Yellownape
Blue-cheeked/Blue-tailed Bee-eater
Eurasian/Red Collared-Dove
Caspian/Yellow-legged/Armenian Gull
Brown-headed/White-cheeked Barbet
Spot-breasted/White-browed Fantail
Brown Goshawk/Collared Sparrowhawk
Alexandrine/Rose-ringed Parakeet
Cassin's/Western Kingbird
Tree/Violet-green Swallow
Slender-billed/Black-headed Gull
Blue-winged/Cinnamon Teal
yellow-bellied kingbird sp.
Spizella sp./American Tree Sparrow
Iduna/Hippolais/Acrocephalus sp.
White-crowned/White-throated Sparrow
Chestnut-tailed/Malabar Starling
Goldcrest/Common Firecrest
cuckoo sp. (Cuculidae sp.)
Red-naped/Red-breasted Sapsucker
Rose-breasted/Black-headed Grosbeak
Yellow-crowned/Black-crowned Night Heron
Lemon-rumped/Sichuan Leaf Warbler
Red-shouldered/Broad-winged Hawk
Pale-legged/Sakhalin Leaf Warbler
Eurasian/Short-toed Treecreeper
Tasmanian/Brown Thornbill
Cooper's Hawk/American Goshawk
Lesser/Greater Racket-tailed Drongo
Spotted/Eastern Towhee (Rufous-sided Towhee)
Red-winged/Tricolored Blackbird
Caspian/Yellow-legged Gull
Herring/Yellow-legged Gull
European/Siberian Stonechat
Red-rumped/Striated Swallow
Western/Glaucous-winged Gull
Yellow-browed/Hume's Warbler
White-browed/White Wagtail
Eastern Cattle/Medium Egret
Indian/Greater Spotted Eagle
Common/Iberian Chiffchaff
Common/Red-breasted Merganser
Lesser/Greater Yellowlegs
Rufous/Allen's Hummingbird
Great/Double-crested Cormorant
Ruby-crowned/Golden-crowned Kinglet
Mallard/American Black Duck
new world martin sp. (Progne sp.)
Downy/Ladder-backed Woodpecker
Yellow-bellied/Red-naped Sapsucker
Golden-fronted/Red-bellied Woodpecker
Microtarsus/Rubigula/Pycnonotus sp.
House/Eurasian Tree Sparrow
Caspian/Herring/Yellow-legged Gull
Common/Barrow's Goldeneye
Short-billed/Long-billed Dowitcher
Northern Cardinal/Pyrrhuloxia
Ruby-throated/Black-chinned Hummingbird
Jungle/Yellow-billed Babbler
Varied Thrush/American Robin
Western/Chihuahuan Meadowlark
Red-whiskered/Red-vented Bulbul
Domestic goose sp. (Domestic type)
Black-capped/Mountain Chickadee
Carolina/Black-capped Chickadee
Western/Eastern Yellow Wagtail
Anna's/Costa's Hummingbird
moorhen/coot/gallinule sp.
Yellow-legged/Lesser Black-backed Gull
Eurasian/African Collared-Dove
Southern/Northern Giant-Petrel
Double-crested/Neotropic Cormorant
Richard's/Paddyfield Pipit
Willow Warbler/Common Chiffchaff
Taiga/Red-breasted Flycatcher
Swinhoe's/Pin-tailed Snipe
Siberian/Tibetan Sand-Plover
Tufted/Black-crested Titmouse
Hutton's/Fluttering Shearwater
Tropical/Couch's Kingbird
European/Spotless Starling
Black-headed/Brown-headed Gull
Western/Eastern Meadowlark
Paddyfield/Blyth's Reed Warbler
Asian Barred/Jungle Owlet
Lesser/Greater Roadrunner
Bullock's/Black-backed Oriole
Bronzed/Brown-headed Cowbird
Sharp-shinned/Cooper's Hawk
