ABA Difficulties (5
is most Difficult)
[Sorted by Code
and Taxonomic Order]
5 Wandering Albatross 5 Shy Albatross 5 Black-browed Albatross 5 Herald Petrel 5 Stejneger's Petrel 5 White-chinned Petrel 5 Streaked Shearwater 5 Wedge-tailed Shearwater 5 Little Shearwater 5 European Storm-Petrel 5 Wedge-rumped Storm-Petrel 5 Red-tailed Tropicbird 5 Great Frigatebird 5 Lesser Frigatebird 5 Yellow Bittern 5 Chinese Egret 5 Little Egret 5 Western Reef-Heron 5 Scarlet Ibis 5 Jabiru 5 Pink-footed Goose 5 Lesser White-fronted Goose 5 Falcated Duck 5 Spot-billed Duck 5 Baikal Teal 6 Labrador Duck 5 Steller's Sea-Eagle 5 Crane Hawk 5 Roadside Hawk 5 Collared Forest-Falcon 5 Eurasian Kestrel 5 Aplomado Falcon 5 Eurasian Hobby 2 Plain Chachalaca 5 Himalayan Snowcock 5 Corn Crake 5 Paint-billed Crake 5 Spotted Rail 5 Azure Gallinule 5 Eurasian Coot 5 Common Crane 5 Double-striped Thick-knee 5 Northern Lapwing 5 European Golden-Plover 5 Collared Plover 5 Little Ringed Plover 5 Eurasian Oystercatcher 5 Black-winged Stilt 5 Oriental Pratincole 5 Marsh Sandpiper 5 Green Sandpiper 5 Little Curlew 5 Eskimo Curlew 5 Slender-billed Curlew 5 Far Eastern Curlew 5 Eurasian Curlew 5 Great Knot 5 Spoonbill Sandpiper 5 Broad-billed Sandpiper 5 Jack Snipe 5 Pin-tailed Snipe 5 Eurasian Woodcock 5 Band-tailed Gull 5 Yellow-legged Gull 5 Large-billed Tern 5 White-winged Tern 6 Great Auk 5 Scaly-naped Pigeon 5 European Turtle-Dove 5 Oriental Turtle-Dove 5 Zenaida Dove 6 Passenger Pigeon 5 Key West Quail-Dove 5 Ruddy Quail-Dove 5 Thick-billed Parrot 5 Common Cuckoo 5 Oriental Cuckoo 5 Oriental Scops-Owl 5 Mottled Owl 5 Jungle Nightjar 5 White-collared Swift 5 White-throated Needletail 5 Common Swift 5 Fork-tailed Swift 5 Antillean Palm Swift 5 Green-breasted Mango 5 Xantus's Hummingbird 5 Cinnamon Hummingbird 5 Bahama Woodstar 5 Bumblebee Hummingbird 5 Eared Trogon 5 Hoopoe 5 Eurasian Wryneck 5 Great Spotted Woodpecker 6 Ivory-billed Woodpecker 5 Greenish Elaenia 5 Caribbean Elaenia 5 Tufted Flycatcher 5 La Sagra's Flycatcher 5 Variegated Flycatcher 5 Nutting's Flycatcher 5 Loggerhead Kingbird 5 Masked Tityra 5 Brown Shrike 5 Thick-billed Vireo 5 Yucatan Vireo 5 Cuban Martin 5 Gray-breasted Martin 5 Southern Martin 5 Brown-chested Martin 5 Common House-Martin 5 Middendorff's Grasshopper-Warbler 5 Lanceolated Warbler 5 Wood Warbler 5 Dusky Warbler 5 Narcissus Flycatcher 5 Mugimaki Flycatcher 5 Red-breasted Flycatcher 5 Siberian Flycatcher 5 Gray-spotted Flycatcher 5 Asian Brown Flycatcher 5 Siberian Blue Robin 5 Red-flanked Bluetail 5 Stonechat 5 Fieldfare 5 Redwing 5 White-throated Robin 5 Aztec Thrush 5 Bahama Mockingbird 5 Blue Mockingbird 5 Siberian Accentor 5 Citrine Wagtail 5 Gray Wagtail 5 Tree Pipit 5 Pechora Pipit 5 Gray Silky-flycatcher 6 Bachman's Warbler 5 Crescent-chested Warbler 5 Gray-crowned Yellowthroat 5 Slate-throated Redstart 5 Fan-tailed Warbler 5 Golden-crowned Warbler 5 Flame-colored Tanager 5 Yellow-faced Grassquit 5 Black-faced Grassquit 5 Worthen's Sparrow 5 Pine Bunting 5 Little Bunting 5 Yellow-breasted Bunting 5 Gray Bunting 5 Pallas's Bunting 5 Reed Bunting 5 Yellow Grosbeak 5 Tawny-shouldered Blackbird 5 Black-vented Oriole 5 Streak-backed Oriole 5 Common Chaffinch 5 Common Rosefinch 5 Eurasian Siskin 5 Oriental Greenfinch 5 Eurasian Bullfinch |
4 Arctic Loon 4 Laysan Albatross 4 Short-tailed Albatross 4 Yellow-nosed Albatross 4 Mottled Petrel 4 Murphy's Petrel 4 Cook's Petrel 4 White-faced Storm-Petrel 4 Band-rumped Storm-Petrel 4 Least Storm-Petrel 4 White-tailed Tropicbird 4 Red-billed Tropicbird 4 Blue-footed Booby 4 Red-footed Booby 4 Greater Flamingo 4 Bean Goose 4 Barnacle Goose 4 Whooper Swan 4 Muscovy Duck 4 White-cheeked Pintail 4 Garganey 4 Common Pochard 4 Smew 4 Masked Duck 4 White-tailed Eagle 4 Mongolian Plover 4 Common Ringed Plover 4 Eurasian Dotterel 4 Northern Jacana 4 Common Greenshank 4 Spotted Redshank 4 Wood Sandpiper 4 Gray-tailed Tattler 4 Common Sandpiper 4 Terek Sandpiper 4 Bristle-thighed Curlew 4 Black-tailed Godwit 4 Red-necked Stint 4 Little Stint 4 Temminck's Stint 4 Long-toed Stint 4 Curlew Sandpiper 4 Slaty-backed Gull 4 Black Noddy 4 Craveri's Murrelet 4 Whiskered Auklet 4 Ruddy Ground-Dove 4 Buff-collared Nightjar 4 Green Violet-ear 4 White-eared Hummingbird 4 Berylline Hummingbird 4 Plain-capped Starthroat 4 Siberian Rubythroat 4 Bluethroat 4 Eyebrowed Thrush 4 Dusky Thrush 4 Clay-colored Robin 4 Rufous-backed Robin 4 Black-backed Wagtail 4 Fork-tailed Flycatcher 4 Eurasian Jackdaw 4 Bahama Swallow 4 Siberian Tit 4 Black-capped Gnatcatcher 4 Olive-backed Pipit 4 Rufous-capped Warbler 4 Bananaquit 4 Stripe-headed Tanager 4 White-collared Seedeater 4 Rustic Bunting 4 Blue Bunting 4 Shiny Cowbird 4 Brambling 4 Hawfinch |
3 Black-footed Albatross 3 Black-capped Petrel 3 Flesh-footed Shearwater 3 Buller's Shearwater 3 Masked Booby 3 Brown Booby 3 Tufted Duck 3 Spectacled Eider 3 Hook-billed Kite 3 Gyrfalcon 3 Yellow Rail 3 Black Rail 3 Bar-tailed Godwit 3 Sharp-tailed Sandpiper 3 Ruff 3 Great Skua 3 South Polar Skua 3 Little Gull 3 Lesser Black-backed Gull 3 Yellow-footed Gull 3 Ross's Gull 3 Ivory Gull 3 Bridled Tern 3 Brown Noddy 3 Red-billed Pigeon 3 Mangrove Cuckoo 3 Ferruginous Pygmy-Owl 3 Great Gray Owl 3 Boreal Owl 3 Antillean Nighthawk 3 Violet-crowned Hummingbird 3 Elegant Trogon 3 Yellow-green Vireo 3 Tamaulipas Crow 3 Sky Lark 3 Northern Wheatear 3 Yellow Wagtail 3 White Wagtail 3 Red-throated Pipit 3 Colima Warbler 3 Tropical Parula 3 Kirtland's Warbler 3 Connecticut Warbler 3 Five-striped Sparrow 3 McKay's Bunting |
2 Yellow-billed Loon 2 Least Grebe 2 Northern Fulmar 2 Cory's Shearwater 2 Pink-footed Shearwater 2 Greater Shearwater 2 Short-tailed Shearwater 2 Manx Shearwater 2 Black-vented Shearwater 2 Audubon's Shearwater 2 Wilson's Storm-Petrel 2 Fork-tailed Storm-Petrel 2 Leach's Storm-Petrel 2 Ashy Storm-Petrel 2 Black Storm-Petrel 2 Red-faced Cormorant 2 Emperor Goose 2 Steller's Eider 2 Snail Kite 2 Common Black-Hawk 2 Short-tailed Hawk 2 White-tailed Hawk 2 Zone-tailed Hawk 2 Crested Caracara 2 Merlin 2 Peregrine Falcon 2 Sage Grouse 2 Spruce Grouse 2 White-tailed Ptarmigan 2 Greater Prairie-chicken 2 Lesser Prairie-chicken 2 Sharp-tailed Grouse 2 Montezuma Quail 2 Mountain Quail 2 Clapper Rail 2 King Rail 2 Limpkin 2 Whooping Crane 2 Mountain Plover 2 Red Phalarope 2 Pomarine Jaeger 2 Parasitic Jaeger 2 Long-tailed Jaeger 2 Thayer's Gull 2 Iceland Gull 2 Red-legged Kittiwake 2 Sabine's Gull 2 Elegant Tern 2 Roseate Tern 2 Aleutian Tern 2 Sooty Tern 2 Dovekie 2 Thick-billed Murre 2 Razorbill 2 Black Guillemot 2 Kittlitz's Murrelet 2 Xantus's Murrelet 2 Ancient Murrelet 2 Cassin's Auklet 2 Parakeet Auklet 2 Least Auklet 2 Crested Auklet 2 Atlantic Puffin 2 Horned Puffin 2 White-tipped Dove 2 Budgerigar 2 Canary-winged Parakeet 2 Red-crowned Parrot 2 Smooth-billed Ani 2 Groove-billed Ani 2 Barn Owl 2 Flammulated Owl 2 Eastern Screech-Owl 2 Western Screech-Owl 2 Whiskered Screech-Owl 2 Snowy Owl 2 Northern Hawk Owl 2 Northern Pygmy-Owl 2 Elf Owl 2 Spotted Owl 2 Long-eared Owl 2 Short-eared Owl 2 Northern Saw-whet Owl 2 Pauraque 2 Common Poorwill 2 Chuck-will's-widow 2 Whip-poor-will 2 Black Swift 2 Broad-billed Hummingbird 2 Buff-bellied Hummingbird 2 Blue-throated Hummingbird 2 Magnificent Hummingbird 2 Lucifer Hummingbird 2 Ringed Kingfisher 2 Green Kingfisher 2 Red-cockaded Woodpecker 2 Three-toed Woodpecker 2 Northern Beardless-Tyrannulet 2 Greater Pewee 2 Buff-breasted Flycatcher 2 Dusky-capped Flycatcher 2 Great Kiskadee 2 Sulphur-bellied Flycatcher 2 Tropical Kingbird 2 Couch's Kingbird 2 Thick-billed Kingbird 2 Gray Kingbird 2 Rose-throated Becard 2 Black-capped Vireo 2 Black-whiskered Vireo 2 Green Jay 2 Brown Jay 2 Mexican Jay 2 Pinyon Jay 2 Crested Myna 2 Bendire's Thrasher 2 Le Conte's Thrasher 2 Sprague's Pipit 2 Mexican Chickadee 2 Red-whiskered Bulbul 2 Arctic Warbler 2 Golden-cheeked Warbler 2 Swainson's Warbler 2 Red-faced Warbler 2 Hepatic Tanager 2 Olive Sparrow 2 Bachman's Sparrow 2 Botteri's Sparrow 2 Rufous-winged Sparrow 2 Black-chinned Sparrow 2 Baird's Sparrow 2 Henslow's Sparrow 2 Le Conte's Sparrow 2 Smith's Longspur 2 Varied Bunting 2 Spot-breasted Oriole 2 Altamira Oriole 2 Audubon's Oriole 2 Hoary Redpoll 2 Eurasian Tree Sparrow |