Ducks, Geese & Swans in Colorado
Our list for Colorado has 28 ducks, geese & swans recorded regularly there: 3 residents, 2 summer visitors, 20 winter visitors and 3 passage migrants
Most likely in October
GBIF · OctShare of all bird records in Colorado in October, 2019–2024. Each month links to that month’s page.
All 28, most common first
Canada GooseBranta canadensisResidentCommon76–110 cmRecorded all year
MallardAnas platyrhynchosResidentCommon50–65 cmRecorded all year
GoldeneyeBucephala clangulaWinter visitorCommon40–51 cmRegularly Nov–Apr
Cackling GooseBranta hutchinsiiWinter visitorCommon53–76 cmRegularly Oct–Mar
GadwallMareca streperaWinter visitorCommon46–56 cmRecorded all year
Common MerganserMergus merganserWinter visitorCommon58–68 cmRecorded all year
Hooded MerganserLophodytes cucullatusWinter visitorCommon40–49 cmRegularly Oct–Apr
Northern ShovelerSpatula clypeataWinter visitorCommon44–51 cmRegularly Aug–Jun
Eurasian TealAnas creccaWinter visitorCommon34–38 cmRegularly Aug–Jun
Cinnamon TealSpatula cyanopteraSummer visitorCommon36–43 cmRegularly Feb–Sep
Ruddy DuckOxyura jamaicensisWinter visitorCommon35–43 cmRecorded all year
Northern PintailAnas acutaWinter visitorUncommon59–76 cmRegularly Aug–Jun
Snow GooseAnser caerulescensWinter visitorUncommon69–84 cmRegularly Oct–Apr
Wood DuckAix sponsaResidentUncommon47–54 cmRecorded all year
Red-breasted MerganserMergus serratorWinter visitorUncommon52–58 cmRegularly Oct–Apr
Greater White-fronted GooseAnser albifronsWinter visitorUncommon64–81 cmRegularly Oct–Apr
Ross's GooseAnser rossiiWinter visitorUncommon57–64 cmRegularly Oct–Apr
Greater ScaupAythya marilaWinter visitorUncommon39–56 cmRegularly Oct–Apr
Long-tailed DuckClangula hyemalisWinter visitorUncommon37–60 cmRegularly Nov–Apr
Trumpeter SwanCygnus buccinatorWinter visitorUncommon139–157 cmRegularly Nov–Mar
Tundra SwanCygnus columbianusWinter visitorUncommon120–150 cmRegularly Oct–Mar
Surf ScoterMelanitta perspicillataPassage migrantUncommon48–60 cmRegularly Oct–Dec
Brent GooseBranta berniclaPassage migrantRare55–66 cmRegularly Nov–Jan
Smallest to largest
Length, cm- Eurasian Teal 34–38 cm
- Ruddy Duck 35–43 cm
- Cinnamon Teal 36–43 cm
- Hooded Merganser 40–49 cm
- Goldeneye 40–51 cm
- Eurasian Wigeon 42–51 cm
- Northern Shoveler 44–51 cm
- Greater Scaup 39–56 cm
- Long-tailed Duck 37–60 cm
- Wood Duck 47–54 cm
- Gadwall 46–56 cm
- Surf Scoter 48–60 cm
- Red-breasted Merganser 52–58 cm
- Mallard 50–65 cm
- Brent Goose 55–66 cm
- Ross's Goose 57–64 cm
- Common Merganser 58–68 cm
- Cackling Goose 53–76 cm
- Northern Pintail 59–76 cm
- Greater White-fronted Goose 64–81 cm
- Muscovy Duck 66–84 cm
- Snow Goose 69–84 cm
- Greylag Goose 75–90 cm
- Swan Goose 81–94 cm
- Canada Goose 76–110 cm
- Tundra Swan 120–150 cm
- Trumpeter Swan 139–157 cm
- Mute Swan 140–160 cm
Body length, bill to tail. Rare birds in grey.
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