- La Selle Thrush
- Labrador Duck
- Lapland Longspur
- Large Ground Finch
- Least Bittern
- Least Grebe
- Least Poorwill
- LeConte's Thrasher
- Lesser Scaup
- Lesser Striped Swallow
- Lesser Swallow-tailed Swift
- Lewis's Woodpecker
- Lidth's Jay
- Light-vented Bulbul
- Lilac-breasted Roller
- Little Auk
- Loggerhead Shrike
- Long-billed Dowitcher
- Long-billed Thrasher
- Long-billed Wren
- Long-eared Owl
- Long-tailed Broadbill
- Long-tailed Mockingbird
- Long-tailed Shrike
- Long-tailed Silky-flycatcher
- Louisiana Waterthrush
- Lühder's Bushshrike