- Baird's Sandpiper
- Bald Eagle
- Bald-faced Hornet
- Baltimore Checkerspot
- Baltimore Oriole
- Baltimore Snout
- Bananaquit
- Band-tailed Pigeon
- Band-winged Dragonlet
- Band-winged Meadowhawk
- Banded Demoiselle
- Banded Garden Spider
- Banded Hairstreak
- Banded Harvestman
- Banded Longhorn Beetle
- Banded Peacock
- Banded Tussock Moth
- Banded Watersnake
- Bank Swallow
- Bar-tailed Godwit
- Bare-faced Ibis
- Bare-throated Tiger-Heron
- Barn Swallow
- Barnacle Goose
- Barred Grass Snake
- Barred Owl
- Barred Yellow
- Barrow's Goldeneye
- Bat Star
- Bath White
- Bathroom Moth Fly
- Bay-breasted Warbler
- Beautiful Demoiselle
- Beautiful Hook-tip
- Beautiful Wood-nymph
- Bedstraw Hawkmoth
- Bee Moth
- Bee-eating Beetle
- Bee-eating Beetle
- Beech Gall Midge
- Beech Leaf Disease
- Beet Armyworm Moth
- Behr's Metalmark
- Belted Grass-veneer
- Belted Kingfisher
- Belted Springtail
- Bent-line Gray
- Bent-lined Carpet
- Berylline Hummingbird
- Bewick's Wren
- Bicolored Sallow
- Bicolored Striped Sweat Bee
- Bighorn Sheep
- Birch Catkin Bug
- Bird-cherry Ermine
- Bishop's Mitre Shield Bug
- Black Arches
- Black Banded Bee Fly
- Black Bulbul
- Black Crappie
- Black Drongo
- Black Firefly
- Black Guillemot
- Black Horse Fly
- Black Kite
- Black Meadowhawk
- Black Oil Beetle
- Black Oystercatcher
- Black Phoebe
- Black Rat
- Black Redstart
- Black Saddlebags
- Black Scoter
- Black Skimmer
- Black Slug
- Black snail beetle
- Black Soldier Fly
- Black Spiny-tailed Iguana
- Black Swallowtail
- Black Swan
- Black Tegula
- Black Tern
- Black Turnstone
- Black Vine Weevil
- Black Vulture
- Black Witch
- Black Woodpecker
- Black-and-gold Bumble Bee
- Black-and-gold Flat Millipede
- Black-and-white Warbler
- Black-bellied Plover
- Black-bellied Whistling-Duck
- Black-billed Magpie
- Black-bordered Lemon Moth
- Black-capped Chickadee
- Black-chinned Hummingbird
- Black-collared Starling
- Black-crested Titmouse
- Black-crowned Night Heron
- Black-dotted Glyph
- Black-faced Cuckooshrike
- Black-headed Cardinal Beetle
- Black-headed Grosbeak
- Black-headed Gull
- Black-headed Heron
- Black-legged Kittiwake
- Black-margined Flower Fly
- Black-naped Oriole
- Black-necked Stilt
- Black-shouldered Drone Fly
- Black-shouldered Kite
- Black-shouldered Shieldbug
- Black-shouldered Spinyleg
- Black-striped Longhorn Beetle
- Black-tailed Bumble Bee
- Black-tailed Godwit
- Black-tailed Gull
- Black-tailed Jackrabbit
- Black-tailed Prairie Dog
- Black-tailed Skimmer
- Black-throated Blue Warbler
- Black-throated Gray Warbler
- Black-throated Green Warbler
- Black-throated Sparrow
- Black-veined Moth
- Black-veined White
- Black-winged Kite
- Black-winged Stilt
- Blackberry Looper Moth
- Blackburnian Warbler
- Blackpoll Warbler
- Blacksmith Lapwing
- Blackspotted Longhorn Beetle
- Blanchard's Cricket Frog
- Blinded Sphinx
- Blood Vein
- Blue Corporal
- Blue Dacnis
- Blue Dasher
- Blue Emperor
- Blue Featherleg
- Blue Grosbeak
- Blue Jay
- Blue Land Crab
- Blue Marsh Hawk
- Blue Mussel
- Blue Pansy
- Blue Rock-Thrush
- Blue Skimmer
- Blue Tiger
- Blue-and-white Swallow
- Blue-black Grassquit
- Blue-eyed Darner
- Blue-eyed Ensign Wasp
- Blue-faced Honeyeater
- Blue-fronted Dancer
- Blue-gray Gnatcatcher
- Blue-gray Tanager
- Blue-headed Vireo
- Blue-ringed Dancer
- Blue-spotted Cornetfish
- Blue-tailed Bee-eater
- Blue-tailed Damselfly
- Blue-tipped Dancer
- Blue-winged Grasshopper
- Blue-winged Scoliid Wasp
- Blue-winged Teal
- Blueband Hermit Crab
- Bluefin Leatherjacket
- Bluegill
- Bluegrass Webworm Moth
- Bluethroat
- Blyth's Reed Warbler
- Boat-billed Flycatcher
- Boat-tailed Grackle
- Bobcat
- Bobolink
- Bohemian Waxwing
- Boisduval's Blue
- Bold Jumping Spider
- Bonaparte's Gull
- Booted Eagle
- Booted Warbler
- Bordered Patch
- Box Bug
- Box Tree Moth
- Brahminy Kite
- Brambling
- Brandt's Cormorant
- Brant
- Brazilian Teal
- Brewer's Blackbird
- Brewer's Sparrow
- Brickwork Woodlouse
- Bright-line Brown-eye
- Bright-spotted groundbug
- Brilliant Jumping Spider
- Brimstone Moth
- Brindled Beauty Moth
- Bristly Cutworm Moth
- Broad Centurion Fly
- Broad Green-winged Grasshopper
- Broad Scarlet
- Broad-billed Hummingbird
- Broad-bodied Chaser
- Broad-bordered Yellow Underwing
- Broad-headed Sharpshooter
- Broad-headed Skink
- Broad-necked Root Borer
- Broad-tailed Hummingbird
- Broad-tipped Conehead
- Broad-winged Hawk
- Bronze Beetle
- Bronze Ground Beetle
- Bronze Jumping Spider
- Bronzed Cowbird
- Bronzed Cutworm Moth
- Bronzed Tiger Beetle
- Brook Trout
- Brother Moth
- Brown Anole
- Brown Argus
- Brown Basilisk
- Brown Booby
- Brown Creeper
- Brown Elfin
- Brown Falcon
- Brown Hare
- Brown Hawker
- Brown Honeyeater
- Brown House Moth
- Brown Jay
- Brown Marmorated Stink Bug
- Brown Pansy
- Brown Pelican
- Brown Prionid
- Brown Rat
- Brown Ringlet
- Brown Shrike
- Brown Thornbill
- Brown Thrasher
- Brown Trout
- Brown Widow
- Brown-belted Bumble Bee
- Brown-eared Bulbul
- Brown-headed Cowbird
- Brown-headed Nuthatch
- Brown-hooded Gull
- Brown-hooded Owlet
- Brown-lipped Snail
- Brown-shaded Gray
- Brown-tail Moth
- Brown-throated Three-toed Sloth
- Brush Rabbit
- Buff Ermine
- Buff-banded Rail
- Buff-tailed Bumble Bee
- Buff-tip
- Buffalo Treehopper
- Bufflehead
- Bullock's Oriole
- Burnet Companion
- Burrowing Owl
- Bush snail
- Bush Stone-curlew
- Bushtit
- Button's Banana Slug
- Buzzing Spider
- By-the-wind Sailor