Rare Birds in Colorado
Our list for Colorado has 72 rare birds recorded regularly there: 10 residents, 13 summer visitors, 14 winter visitors and 35 passage migrants
Most likely in October
GBIF · Oct
Share of all bird records in Colorado in October, 2019–2024. Each month links to that month’s page.
All 72, most common first
Common RedpollAcanthis flammeaWinter visitorRare12–14 cmRegularly Nov–Mar
Buff-breasted SandpiperCalidris subruficollisPassage migrantRare18–20 cmRegularly Aug–Sep
Northern Saw-whet OwlAegolius acadicusResidentRare17–21 cmRecorded all year
Short-eared OwlAsio flammeusWinter visitorRare34–43 cmRegularly Oct–Jun
Magnolia WarblerSetophaga magnoliaPassage migrantRare11–13 cmRegularly May–Oct
Cattle EgretArdea ibisSummer visitorRare46–56 cmRegularly Apr–Nov
White-rumped SandpiperCalidris fuscicollisPassage migrantRare15–18 cmRegularly May–Jun
Eurasian WigeonMareca penelopePassage migrantRare42–51 cmRegularly Dec–Apr
Palm WarblerSetophaga palmarumPassage migrantRare12–14 cmRegularly Apr–Dec
Long-tailed JaegerStercorarius longicaudusPassage migrantRare48–58 cmRegularly Aug–Sep
Pacific WrenTroglodytes pacificusWinter visitorRare8–12 cmRegularly Jul–Apr
Varied ThrushIxoreus naeviusWinter visitorRare20–26 cmRegularly Oct–Mar
Black-throated Blue WarblerSetophaga caerulescensPassage migrantRare11–13 cmRegularly May–Dec
Flammulated OwlPsiloscops flammeolusSummer visitorRare15–17 cmRegularly May–Sep
WhimbrelNumenius phaeopusPassage migrantRare40–46 cmRegularly Apr–May
Cape May WarblerSetophaga tigrinaPassage migrantRare12–14 cmRegularly Dec–May
Glossy IbisPlegadis falcinellusPassage migrantRare48–66 cmRegularly Apr–May
American BitternBotaurus lentiginosusSummer visitorRare58–85 cmRegularly Apr–Oct
Painted BuntingPasserina cirisPassage migrantRare12–14 cmRegularly May–Aug
Black-throated Green WarblerSetophaga virensPassage migrantRare11–12 cmRegularly May–Oct
Little GullHydrocoloeus minutusPassage migrantRare25–30 cmRegularly Sep
Greylag GooseAnser anserWinter visitorRare75–90 cmRecorded all year
Arctic TernSterna paradisaeaPassage migrantRare33–39 cmRegularly Sep–Oct
Data: EOD – eBird Observation Dataset (Cornell Lab of Ornithology), accessed via GBIF.org, CC BY 4.0. Records from 2019–2024, aggregated and filtered by Birdfact. How these lists are made