Boulder County - 400 species

GEESE
  Greater White-fronted Goose
  Snow Goose
  Ross's Goose
  Brant
  Cackling Goose
  Canada Goose
SWANS
  Trumpeter Swan
  Tundra Swan
DUCKS
  Wood Duck
  Gadwall
  American Wigeon
  Mallard
  Blue-winged Teal
  Cinnamon Teal
  Northern Shoveler
  Northern Pintail
  Garganey
  Green-winged Teal
  Canvasback
  Redhead
  Ring-necked Duck
  Tufted Duck
  Greater Scaup
  Lesser Scaup
  Surf Scoter
  White-winged Scoter
  Black Scoter
  Long-tailed Duck
  Bufflehead
  Common Goldeneye
  Barrow's Goldeneye
  Hooded Merganser
  Common Merganser
  Red-breasted Merganser
  Ruddy Duck
QUAIL
  Northern Bobwhite
PHEASANTS
  Ring-necked Pheasant
GROUSE
  White-tailed Ptarmigan
  Dusky Grouse
  Sharp-tailed Grouse
TURKEYS
  Wild Turkey
LOONS
  Pacific Loon
  Common Loon
  Yellow-billed Loon
GREBES
  Pied-billed Grebe
  Horned Grebe
  Red-necked Grebe
  Eared Grebe
  Western Grebe
  Clark's Grebe
CORMORANTS
  Double-crested Cormorant
PELICANS
  American White Pelican
  Brown Pelican
HERONS
  American Bittern
  Least Bittern
  Great Blue Heron
  Great Egret
  Snowy Egret
  Little Blue Heron
  Cattle Egret
  Green Heron
  Black-crowned Night-Heron
  Yellow-crowned Night-Heron
IBISES
  Glossy Ibis
  White-faced Ibis
VULTURES
  Turkey Vulture
HAWKS
  Osprey
  Mississippi Kite
  Bald Eagle
  Northern Harrier
  Sharp-shinned Hawk
  Cooper's Hawk
  Northern Goshawk
  Red-shouldered Hawk
  Broad-winged Hawk
  Swainson's Hawk
  Red-tailed Hawk
  Ferruginous Hawk
  Rough-legged Hawk
  Golden Eagle
RAILS
  Virginia Rail
  Sora
  Common Gallinule
  American Coot
CRANES
  Sandhill Crane
PLOVERS
  Black-bellied Plover
  American Golden-Plover
  Snowy Plover
  Semipalmated Plover
  Piping Plover
  Killdeer
  Mountain Plover
AVOCETS & STILTS
  Black-necked Stilt
  American Avocet
SANDPIPERS
  Spotted Sandpiper
  Solitary Sandpiper
  Greater Yellowlegs
  Willet
  Lesser Yellowlegs
  Upland Sandpiper
  Whimbrel
  Long-billed Curlew
  Marbled Godwit
  Ruddy Turnstone
  Sanderling
  Semipalmated Sandpiper
  Western Sandpiper
  Least Sandpiper
  White-rumped Sandpiper
  Baird's Sandpiper
  Pectoral Sandpiper
  Sharp-tailed Sandpiper
  Dunlin
  Stilt Sandpiper
  Ruff
  Short-billed Dowitcher
  Long-billed Dowitcher
  Wilson's Snipe
  American Woodcock
  Wilson's Phalarope
  Red-necked Phalarope
  Red Phalarope
GULLS
  Black-legged Kittiwake
  Sabine's Gull
  Bonaparte's Gull
  Black-headed Gull
  Ross's Gull
  Franklin's Gull
  Mew Gull
  Ring-billed Gull
  California Gull
  Herring Gull
  Thayer's Gull
  Iceland Gull
  Lesser Black-backed Gull
  Glaucous-winged Gull
  Glaucous Gull
  Great Black-backed Gull
TERNS
  Least Tern
  Caspian Tern
  Black Tern
  Common Tern
  Arctic Tern
  Forster's Tern
JAEGERS
  Long-tailed Jaeger
MURRELETS
  Ancient Murrelet
PIGEONS & DOVES
  Rock Pigeon
  Band-tailed Pigeon
  Eurasian Collared-Dove
  White-winged Dove
  Mourning Dove
  Inca Dove
CUCKOOS
  Yellow-billed Cuckoo
  Black-billed Cuckoo
BARN OWLS
  Barn Owl
OWLS
  Flammulated Owl
  Eastern Screech-Owl
  Great Horned Owl
  Northern Pygmy-Owl
  Burrowing Owl
  Spotted Owl
  Long-eared Owl
  Short-eared Owl
  Boreal Owl
  Northern Saw-whet Owl
NIGHTJARS
  Lesser Nighthawk
  Common Nighthawk
  Common Poorwill
SWIFTS
  Black Swift
  Chimney Swift
  White-throated Swift
HUMMINGBIRDS
  Magnificent Hummingbird
  Ruby-throated Hummingbird
  Black-chinned Hummingbird
  Anna's Hummingbird
  Broad-tailed Hummingbird
  Rufous Hummingbird
  Calliope Hummingbird
KINGFISHERS
  Belted Kingfisher
WOODPECKERS
  Lewis's Woodpecker
  Red-headed Woodpecker
  Acorn Woodpecker
  Red-bellied Woodpecker
  Williamson's Sapsucker
  Yellow-bellied Sapsucker
  Red-naped Sapsucker
  Ladder-backed Woodpecker
  Downy Woodpecker
  Hairy Woodpecker
  American Three-toed Woodpecker
  Northern Flicker
FALCONS
  American Kestrel
  Merlin
  Gyrfalcon
  Peregrine Falcon
  Prairie Falcon
FLYCATCHERS
  Olive-sided Flycatcher
  Western Wood-Pewee
  Eastern Wood-Pewee
  Alder Flycatcher
  Willow Flycatcher
  Least Flycatcher
  Hammond's Flycatcher
  Gray Flycatcher
  Dusky Flycatcher
  Cordilleran Flycatcher
  Black Phoebe
  Eastern Phoebe
  Say's Phoebe
  Vermilion Flycatcher
  Ash-throated Flycatcher
  Great Crested Flycatcher
  Cassin's Kingbird
  Western Kingbird
  Eastern Kingbird
SHRIKES
  Loggerhead Shrike
  Northern Shrike
VIREOS
  White-eyed Vireo
  Bell's Vireo
  Yellow-throated Vireo
  Plumbeous Vireo
  Cassin's Vireo
  Blue-headed Vireo
  Warbling Vireo
  Philadelphia Vireo
  Red-eyed Vireo
JAYS & CROWS
  Gray Jay
  Pinyon Jay
  Steller's Jay
  Blue Jay
  Western Scrub-Jay
  Clark's Nutcracker
  Black-billed Magpie
  American Crow
  Chihuahuan Raven
  Common Raven
LARKS
  Horned Lark
SWALLOWS
  Purple Martin
  Tree Swallow
  Violet-green Swallow
  Northern Rough-winged Swallow
  Bank Swallow
  Cliff Swallow
  Barn Swallow
CHICKADEES
  Black-capped Chickadee
  Mountain Chickadee
  Juniper Titmouse
BUSHTITS
  Bushtit
NUTHATCHES
  Red-breasted Nuthatch
  White-breasted Nuthatch
  Pygmy Nuthatch
CREEPERS
  Brown Creeper
WRENS
  Rock Wren
  Canyon Wren
  House Wren
  Pacific Wren
  Winter Wren
  Sedge Wren
  Marsh Wren
  Carolina Wren
  Bewick's Wren
GNATCATCHERS
  Blue-gray Gnatcatcher
DIPPERS
  American Dipper
KINGLETS
  Golden-crowned Kinglet
  Ruby-crowned Kinglet
THRUSHES
  Eastern Bluebird
  Western Bluebird
  Mountain Bluebird
  Townsend's Solitaire
  Veery
  Gray-cheeked Thrush
  Swainson's Thrush
  Hermit Thrush
  Wood Thrush
  American Robin
  Varied Thrush
THRASHERS
  Gray Catbird
  Northern Mockingbird
  Sage Thrasher
  Brown Thrasher
  Curve-billed Thrasher
STARLINGS
  European Starling
PIPITS
  American Pipit
  Sprague's Pipit
WAXWINGS
  Bohemian Waxwing
  Cedar Waxwing
SILKY-FLYCATCHERS
  Phainopepla
LONGSPURS
  Lapland Longspur
  Chestnut-collared Longspur
  McCown's Longspur
  Snow Bunting
WARBLERS
  Ovenbird
  Worm-eating Warbler
  Louisiana Waterthrush
  Northern Waterthrush
  Golden-winged Warbler
  Blue-winged Warbler
  Black-and-white Warbler
  Prothonotary Warbler
  Swainson's Warbler
  Tennessee Warbler
  Orange-crowned Warbler
  Nashville Warbler
  Virginia's Warbler
  Connecticut Warbler
  MacGillivray's Warbler
  Mourning Warbler
  Kentucky Warbler
  Common Yellowthroat
  Hooded Warbler
  American Redstart
  Cape May Warbler
  Northern Parula
  Magnolia Warbler
  Bay-breasted Warbler
  Blackburnian Warbler
  Yellow Warbler
  Chestnut-sided Warbler
  Blackpoll Warbler
  Black-throated Blue Warbler
  Palm Warbler
  Pine Warbler
  Yellow-rumped Warbler
  Yellow-throated Warbler
  Prairie Warbler
  Grace's Warbler
  Black-throated Gray Warbler
  Townsend's Warbler
  Hermit Warbler
  Black-throated Green Warbler
  Canada Warbler
  Wilson's Warbler
  Yellow-breasted Chat
SPARROWS
  Green-tailed Towhee
  Spotted Towhee
  Eastern Towhee
  Canyon Towhee
  Cassin's Sparrow
  American Tree Sparrow
  Chipping Sparrow
  Clay-colored Sparrow
  Brewer's Sparrow
  Field Sparrow
  Vesper Sparrow
  Lark Sparrow
  Black-throated Sparrow
  Sage Sparrow
  Lark Bunting
  Savannah Sparrow
  Grasshopper Sparrow
  Baird's Sparrow
  Fox Sparrow
  Song Sparrow
  Lincoln's Sparrow
  Swamp Sparrow
  White-throated Sparrow
  Harris's Sparrow
  White-crowned Sparrow
  Golden-crowned Sparrow
  Dark-eyed Junco
CARDINALS
  Hepatic Tanager
  Summer Tanager
  Scarlet Tanager
  Western Tanager
  Northern Cardinal
  Rose-breasted Grosbeak
  Black-headed Grosbeak
  Blue Grosbeak
  Lazuli Bunting
  Indigo Bunting
  Painted Bunting
  Dickcissel
BLACKBIRDS
  Bobolink
  Red-winged Blackbird
  Western Meadowlark
  Yellow-headed Blackbird
  Rusty Blackbird
  Brewer's Blackbird
  Common Grackle
  Great-tailed Grackle
  Brown-headed Cowbird
  Orchard Oriole
  Bullock's Oriole
  Baltimore Oriole
  Scott's Oriole
FINCHES
  Brambling
  Gray-crowned Rosy-Finch
  Black Rosy-Finch
  Brown-capped Rosy-Finch
  Pine Grosbeak
  Purple Finch
  Cassin's Finch
  House Finch
  Red Crossbill
  White-winged Crossbill
  Pine Siskin
  Lesser Goldfinch
  American Goldfinch
  Evening Grosbeak
OLD WORLD SPARROWS
  House Sparrow