- Baird's Flycatcher
- Baird's Sandpiper
- Bananaquit
- Band-tailed Fruiteater
- Band-tailed Pigeon
- Band-tailed Seedeater
- Band-tailed Sierra Finch
- Band-winged Nightjar
- Bare-faced Ground Dove
- Barred Becard
- Barred Warbler
- Beaudouin's Snake Eagle
- Belcher's Gull
- Beryl-spangled Tanager
- Black-and-white Becard
- Black-billed Shrike-Tyrant
- Black-billed Thrush
- Black-billed Wood Dove
- Black-breasted Hillstar
- Black-browed Albatross
- Black-capped Hemispingus
- Black-chested Buzzard-Eagle
- Black-chinned Siskin
- Black-cowled Saltator
- Black-crested Tit-Tyrant
- Black-crowned Night Heron
- Black-faced Ibis
- Black-fronted Ground Tyrant
- Black-fronted Nunbird
- Black-headed Lapwing
- Black-hooded Sierra Finch
- Black-necked Stilt
- Black-necked Swan
- Black-necked Woodpecker
- Black-throated Hermit
- Black-throated Mango
- Black-throated Toucanet
- Black-winged Ground Dove
- Black Kite
- Black Metaltail
- Black Oystercatcher
- Black Rail
- Black Siskin
- Black Skimmer
- Black Vulture
- Blackish Oystercatcher
- Blue-and-white Swallow
- Blue-and-yellow Tanager
- Blue-banded Toucanet
- Blue-black Grassquit
- Blue-breasted Kingfisher
- Blue-capped Tanager
- Blue-cheeked Bee-eater
- Blue-footed Booby
- Blue-fronted Lancebill
- Blue-grey Tanager
- Blue-headed Parrot
- Blue-spotted Wood Dove
- Blue-tailed Emerald
- Blue Dacnis
- Bluish-fronted Jacamar
- Bluish-grey Saltator
- Boat-billed Flycatcher
- Bright-rumped Yellow Finch
- Bronzy Inca
- Brown-backed Chat-Tyrant
- Brown-crested Flycatcher
- Brown-hooded Gull
- Brown Pelican
- Brown Violetear
- Buff-bellied Tanager
- Buff-breasted Earthcreeper
- Buff-breasted Mountain Tanager
- Buff-breasted Sandpiper
- Buff-bridled Inca Finch
- Buff-winged Cinclodes
- Buller's Albatross
- Burrowing Owl