Birds to See in Colorado in September
166 bird species on our list for Colorado are recorded regularly in September
Of these, the most often recorded are Northern Flicker, House Finch, American Robin, Blue Jay and Mallard. New this month: American Herring Gull, Swainson's Thrush, Merlin and Lesser Black-backed Gull and 18 more.
On the move in September
GBIF · SepArriving
At their peak
Chipping SparrowBusiest month of the year · Apr–Oct
Turkey VultureBusiest month of the year · Mar–Oct
Vesper SparrowBusiest month of the year · Apr–Oct
Orange-crowned WarblerBusiest month of the year · Apr–Oct
Clay-colored SparrowBusiest month of the year · May
Great White EgretBusiest month of the year · Apr–Oct
From Colorado’s bird records, 2019–2024: arriving birds are regular this month but not last; leaving birds are regular this month but not next.
Other months
All 166 birds in September
166 birds
Northern FlickerColaptes auratusResidentCommon28–31 cmRecorded all year · 3.14% in Sep
House FinchHaemorhous mexicanusResidentCommon13–15 cmRecorded all year · 2.67% in Sep
American RobinTurdus migratoriusResidentCommon20–28 cmRecorded all year · 2.35% in Sep
Blue JayCyanocitta cristataResidentCommon25–30 cmRecorded all year · 2.27% in Sep
MallardAnas platyrhynchosResidentCommon50–65 cmRecorded all year · 2.23% in Sep
Mourning DoveZenaida macrouraSummer visitorCommon23–34 cmRecorded all year · 2.01% in Sep
Canada GooseBranta canadensisResidentCommon76–110 cmRecorded all year · 1.75% in Sep
American CrowCorvus brachyrhynchosResidentCommon41–53 cmRecorded all year · 1.68% in Sep
Red-tailed HawkButeo jamaicensisResidentCommon45–65 cmRecorded all year · 1.68% in Sep
Barn SwallowHirundo rusticaSummer visitorCommon17–19 cmRegularly Apr–Oct · 1.66% in Sep
Eurasian Collared DoveStreptopelia decaoctoResidentCommon30–32 cmRecorded all year · 1.59% in Sep
Common StarlingSturnus vulgarisResidentCommon21–23 cmRecorded all year · 1.56% in Sep
White-breasted NuthatchSitta carolinensisResidentCommon13–14 cmRecorded all year · 1.48% in Sep
Great Blue HeronArdea herodiasResidentCommon91–137 cmRecorded all year · 1.34% in Sep- Chipping SparrowSpizella passerinaSummer visitorCommon12–15 cmRegularly Apr–Oct · 1.32% in Sep
Red-winged BlackbirdAgelaius phoeniceusResidentCommon17–23 cmRecorded all year · 1.32% in Sep
Common RavenCorvus coraxResidentCommon54–67 cmRecorded all year · 1.31% in Sep
Yellow-rumped WarblerSetophaga coronataSummer visitorCommon12–15 cmRecorded all year · 1.29% in Sep
Downy WoodpeckerDryobates pubescensResidentCommon14–18 cmRecorded all year · 1.27% in Sep- Turkey VultureCathartes auraSummer visitorCommon62–81 cmRegularly Mar–Oct · 1.20% in Sep
Ring-billed GullLarus delawarensisWinter visitorCommon43–54 cmRegularly Jul–May · 1.19% in Sep
Say's PhoebeSayornis sayaSummer visitorCommon17–20 cmRecorded all year · 1.05% in Sep
Song SparrowMelospiza melodiaResidentCommon12–17 cmRecorded all year · 0.98% in Sep
White-crowned SparrowZonotrichia leucophrysWinter visitorCommon15–16 cmRecorded all year · 0.93% in Sep
Western MeadowlarkSturnella neglectaSummer visitorCommon16–26 cmRecorded all year · 0.88% in Sep- Vesper SparrowPooecetes gramineusSummer visitorCommon13–17 cmRegularly Apr–Oct · 0.87% in Sep
Rock DoveColumba liviaResidentCommon29–37 cmRecorded all year · 0.86% in Sep
House SparrowPasser domesticusResidentCommon14–17 cmRecorded all year · 0.74% in Sep- Orange-crowned WarblerLeiothlypis celataSummer visitorCommon11–14 cmRegularly Apr–Oct · 0.63% in Sep
Pied-billed GrebePodilymbus podicepsWinter visitorCommon31–38 cmRecorded all year · 0.58% in Sep
OspreyPandion haliaetusSummer visitorCommon54–58 cmRegularly Mar–Oct · 0.56% in Sep
Hairy WoodpeckerLeuconotopicus villosusResidentCommon18–26 cmRecorded all year · 0.55% in Sep
Pine SiskinSpinus pinusResidentCommon11–14 cmRecorded all year · 0.53% in Sep
Gray CatbirdDumetella carolinensisSummer visitorCommon20–24 cmRegularly May–Oct · 0.53% in Sep
Ruby-crowned KingletCorthylio calendulaSummer visitorCommon9–11 cmRecorded all year · 0.51% in Sep
Eurasian TealAnas creccaWinter visitorCommon34–38 cmRegularly Aug–Jun · 0.50% in Sep
Common GrackleQuiscalus quisculaSummer visitorCommon28–34 cmRegularly Mar–Oct · 0.49% in Sep
Lincoln's SparrowMelospiza lincolniiSummer visitorCommon13–15 cmRegularly Mar–Dec · 0.47% in Sep
Cedar WaxwingBombycilla cedrorumResidentCommon15–18 cmRecorded all year · 0.45% in Sep
Bald EagleHaliaeetus leucocephalusWinter visitorCommon70–102 cmRecorded all year · 0.45% in Sep
Mountain BluebirdSialia currucoidesSummer visitorCommon15–18 cmRecorded all year · 0.45% in Sep
Western KingbirdTyrannus verticalisSummer visitorCommon20–24 cmRegularly Apr–Sep · 0.45% in Sep
Northern ShovelerSpatula clypeataWinter visitorCommon44–51 cmRegularly Aug–Jun · 0.41% in Sep
Lark SparrowChondestes grammacusSummer visitorCommon15–17 cmRegularly Apr–Sep · 0.41% in Sep
GadwallMareca streperaWinter visitorCommon46–56 cmRecorded all year · 0.39% in Sep
Northern Yellow WarblerSetophaga aestivaSummer visitorCommon12–13 cmRegularly May–Sep · 0.39% in Sep
Horned LarkEremophila alpestrisResidentCommon16–20 cmRecorded all year · 0.37% in Sep
Baird's SandpiperCalidris bairdiiPassage migrantUncommon14–17 cmRegularly Apr–Oct · 0.35% in Sep
Great Horned OwlBubo virginianusResidentUncommon46–63 cmRecorded all year · 0.32% in Sep
Common YellowthroatGeothlypis trichasSummer visitorCommon11–13 cmRegularly May–Oct · 0.29% in Sep
Ruddy DuckOxyura jamaicensisWinter visitorCommon35–43 cmRecorded all year · 0.28% in Sep- Clay-colored SparrowSpizella pallidaPassage migrantUncommon13–15 cmRegularly May–Oct · 0.27% in Sep
Least SandpiperCalidris minutillaPassage migrantUncommon13–15 cmRegularly Apr–Nov · 0.27% in Sep
Common MerganserMergus merganserWinter visitorCommon58–68 cmRecorded all year · 0.25% in Sep
Wood DuckAix sponsaResidentUncommon47–54 cmRecorded all year · 0.24% in Sep
Franklin's GullLeucophaeus pipixcanPassage migrantUncommon32–36 cmRegularly Mar–Nov · 0.23% in Sep
Wild TurkeyMeleagris gallopavoResidentUncommon100–125 cmRecorded all year · 0.23% in Sep- Great White EgretArdea albaSummer visitorUncommon80–104 cmRegularly Apr–Oct · 0.22% in Sep
Red CrossbillLoxia curvirostraResidentUncommon15–17 cmRecorded all year · 0.22% in Sep
Red-naped SapsuckerSphyrapicus nuchalisSummer visitorUncommon19–21 cmRegularly Apr–Oct · 0.22% in Sep
Lesser YellowlegsTringa flavipesPassage migrantUncommon23–27 cmRegularly Apr–Oct · 0.21% in Sep
Greater YellowlegsTringa melanoleucaPassage migrantCommon29–40 cmRegularly Mar–Nov · 0.18% in Sep
American AvocetRecurvirostra americanaSummer visitorCommon43–51 cmRegularly Mar–Oct · 0.18% in Sep
Black-necked GrebePodiceps nigricollisSummer visitorCommon28–34 cmRecorded all year · 0.17% in Sep
Evening GrosbeakHesperiphona vespertinaResidentUncommon16–22 cmRecorded all year · 0.17% in Sep
Pectoral SandpiperCalidris melanotosPassage migrantUncommon19–23 cmRegularly Aug–Nov · 0.16% in Sep
Black-crowned Night-heronNycticorax nycticoraxSummer visitorUncommon58–65 cmRecorded all year · 0.15% in Sep
Sharp-shinned HawkAccipiter striatusWinter visitorUncommon24–34 cmRecorded all year · 0.15% in Sep
Solitary SandpiperTringa solitariaPassage migrantUncommon19–23 cmRegularly Apr–Sep · 0.14% in Sep
Golden EagleAquila chrysaetosResidentUncommon66–102 cmRecorded all year · 0.13% in Sep
Northern PintailAnas acutaWinter visitorUncommon59–76 cmRegularly Aug–Jun · 0.13% in Sep
Hermit ThrushCatharus guttatusSummer visitorUncommon14–18 cmRegularly Apr–Dec · 0.13% in Sep
Sabine's GullXema sabiniPassage migrantUncommon27–33 cmRegularly Aug–Oct · 0.12% in Sep
Stilt SandpiperCalidris himantopusPassage migrantUncommon18–23 cmRegularly May–Oct · 0.12% in Sep
Wilson's PhalaropePhalaropus tricolorSummer visitorUncommon22–24 cmRegularly Apr–Sep · 0.12% in Sep
Long-billed DowitcherLimnodromus scolopaceusPassage migrantUncommon27–30 cmRegularly Mar–Nov · 0.11% in Sep
Peregrine FalconFalco peregrinusSummer visitorUncommon34–58 cmRecorded all year · 0.10% in Sep
Cinnamon TealSpatula cyanopteraSummer visitorCommon36–43 cmRegularly Feb–Sep · 0.10% in Sep
SanderlingCalidris albaPassage migrantUncommon18–20 cmRegularly May–Oct · 0.10% in Sep
Virginia RailRallus limicolaResidentUncommon20–27 cmRecorded all year · 0.10% in Sep
Red-necked PhalaropePhalaropus lobatusPassage migrantUncommon18–19 cmRegularly May–Oct · 0.09% in Sep
Forster's TernSterna forsteriSummer visitorUncommon33–36 cmRegularly Apr–Oct · 0.09% in Sep
Red-headed WoodpeckerMelanerpes erythrocephalusSummer visitorUncommon19–23 cmRegularly May–Oct · 0.08% in Sep
Lewis's WoodpeckerMelanerpes lewisResidentUncommon26–28 cmRecorded all year · 0.08% in Sep
Black TernChlidonias nigerSummer visitorUncommon22–26 cmRegularly May–Sep · 0.08% in Sep
Marsh WrenCistothorus palustrisResidentUncommon10–14 cmRecorded all year · 0.07% in Sep
Semipalmated SandpiperCalidris pusillaPassage migrantUncommon15–18 cmRegularly Apr–Oct · 0.07% in Sep
Sandhill CraneAntigone canadensisWinter visitorUncommon80–122 cmRecorded all year · 0.07% in Sep
Semipalmated PloverCharadrius semipalmatusPassage migrantUncommon17–19 cmRegularly Apr–Oct · 0.07% in Sep
Western SandpiperCalidris mauriPassage migrantUncommon14–17 cmRegularly Apr–Oct · 0.06% in Sep
Swainson's ThrushCatharus ustulatusSummer visitorUncommon16–20 cmRegularly May–Sep · 0.06% in Sep
Northern MockingbirdMimus polyglottosSummer visitorUncommon21–26 cmRegularly Apr–Sep · 0.06% in Sep
Sand MartinRiparia ripariaSummer visitorUncommon12–14 cmRegularly Apr–Sep · 0.06% in Sep
Burrowing OwlAthene cuniculariaSummer visitorUncommon19–25 cmRegularly Mar–Oct · 0.05% in Sep
Ladder-backed WoodpeckerDryobates scalarisSummer visitorUncommon16–19 cmRecorded all year · 0.05% in Sep
Williamson's SapsuckerSphyrapicus thyroideusSummer visitorUncommon21–25 cmRegularly Apr–Jan · 0.05% in Sep
MerlinFalco columbariusWinter visitorUncommon24–33 cmRegularly Sep–Apr · 0.05% in Sep
American RedstartSetophaga ruticillaSummer visitorUncommon11–14 cmRegularly May–Sep · 0.05% in Sep
Grey PloverPluvialis squatarolaPassage migrantUncommon27–30 cmRegularly May–Nov · 0.05% in Sep
Common TernSterna hirundoPassage migrantRare31–35 cmRegularly Jun–Oct · 0.05% in Sep
Nashville WarblerLeiothlypis ruficapillaPassage migrantRare11–13 cmRegularly Apr–Nov · 0.04% in Sep
White-winged DoveZenaida asiaticaResidentUncommon27–30 cmRecorded all year · 0.04% in Sep
Willow FlycatcherEmpidonax trailliiSummer visitorUncommon13–17 cmRegularly May–Sep · 0.04% in Sep
Least FlycatcherEmpidonax minimusSummer visitorUncommon12–14 cmRegularly May–Sep · 0.04% in Sep
Lesser Black-backed GullLarus fuscusWinter visitorUncommon52–64 cmRegularly Sep–Apr · 0.04% in Sep
American Three-toed WoodpeckerPicoides dorsalisSummer visitorUncommon21–24 cmRecorded all year · 0.04% in Sep
American Herring GullLarus smithsonianusWinter visitorUncommon53–65 cmRegularly Sep–Apr · 0.04% in Sep
Marbled GodwitLimosa fedoaSummer visitorUncommon40–50 cmRegularly Apr–Sep · 0.03% in Sep
Northern WaterthrushParkesia noveboracensisPassage migrantUncommon12–15 cmRegularly May–Sep · 0.03% in Sep
Common PheasantPhasianus colchicusResidentUncommon50–90 cmRecorded all year · 0.02% in Sep
American Golden-PloverPluvialis dominicaPassage migrantRare24–28 cmRegularly Sep–Nov · 0.02% in Sep
Buff-breasted SandpiperCalidris subruficollisPassage migrantRare18–20 cmRegularly Aug–Sep · 0.02% in Sep
Broad-winged HawkButeo platypterusPassage migrantRare34–44 cmRegularly Apr–Oct · 0.02% in Sep
Eastern Screech-owlMegascops asioWinter visitorUncommon16–25 cmRecorded all year · 0.02% in Sep
Cattle EgretArdea ibisSummer visitorRare46–56 cmRegularly Apr–Nov · 0.02% in Sep
WilletTringa semipalmataSummer visitorUncommon33–41 cmRegularly Apr–Sep · 0.01% in Sep
Northern Pygmy-owlGlaucidium gnomaResidentRare15–17 cmRecorded all year · 0.01% in Sep
Little GullHydrocoloeus minutusPassage migrantRare25–30 cmRegularly Sep · 0.01% in Sep
Northern CardinalCardinalis cardinalisResidentRare21–23 cmRecorded all year · 0.01% in Sep
Short-billed DowitcherLimnodromus griseusPassage migrantRare23–32 cmRegularly Apr–Sep · 0.01% in Sep
Fox SparrowPasserella iliacaSummer visitorUncommon15–19 cmRecorded all year · 0.01% in Sep
Long-tailed JaegerStercorarius longicaudusPassage migrantRare48–58 cmRegularly Aug–Sep · 0.01% in Sep
Great Crested FlycatcherMyiarchus crinitusSummer visitorRare17–22 cmRegularly May–Sep · 0.01% in Sep
OvenbirdSeiurus aurocapillaSummer visitorUncommon12–15 cmRegularly May–Sep · 0.01% in Sep
DickcisselSpiza americanaSummer visitorUncommon14–16 cmRegularly May–Sep · 0.01% in Sep
American BitternBotaurus lentiginosusSummer visitorRare58–85 cmRegularly Apr–Oct · 0.01% in Sep
Chestnut-sided WarblerSetophaga pensylvanicaPassage migrantRare10–14 cmRegularly May–Oct · 0.01% in Sep
Eastern BluebirdSialia sialisWinter visitorRare16–21 cmRecorded all year · 0.01% in Sep
Baltimore OrioleIcterus galbulaSummer visitorRare17–19 cmRegularly May–Sep · 0.01% in Sep
Philadelphia VireoVireo philadelphicusPassage migrantRare11–13 cmRegularly May–Oct · 0.01% in Sep
Blue-headed VireoVireo solitariusPassage migrantRare12–15 cmRegularly Apr–Oct · 0.01% in Sep
Arctic JaegerStercorarius parasiticusPassage migrantRare41–46 cmRegularly Sep–Oct · 0.01% in Sep
Tennessee WarblerLeiothlypis peregrinaPassage migrantRare10–13 cmRegularly May–Nov · 0.01% in Sep
Northern Saw-whet OwlAegolius acadicusResidentRare17–21 cmRecorded all year · 0.01% in Sep
Red-bellied WoodpeckerMelanerpes carolinusResidentRare23–26 cmRecorded all year · 0.01% in Sep
Ruddy TurnstoneArenaria interpresResidentRare21–24 cmRegularly May–Sep · 0.01% in Sep
Greater RoadrunnerGeococcyx californianusResidentRare52–54 cmRecorded all year · 0.01% in Sep
ChukarAlectoris chukarResidentRare32–38 cmRecorded all year · 0.00% in Sep
Palm WarblerSetophaga palmarumPassage migrantRare12–14 cmRegularly Apr–Dec · 0.00% in Sep
Western Screech-owlMegascops kennicottiiWinter visitorRare19–25 cmRecorded all year · 0.00% in Sep
Arctic TernSterna paradisaeaPassage migrantRare33–39 cmRegularly Sep–Oct · 0.00% in Sep
Upland SandpiperBartramia longicaudaSummer visitorRare28–32 cmRegularly May–Sep · 0.00% in Sep
Rose-breasted GrosbeakPheucticus ludovicianusPassage migrantUncommon18–22 cmRegularly May–Oct · 0.00% in Sep
Red-necked GrebePodiceps grisegenaWinter visitorRare40–50 cmRegularly Jul–Mar · 0.00% in Sep
Red KnotCalidris canutusResidentRare23–26 cmRegularly Aug–Sep · 0.00% in Sep
Boreal OwlAegolius funereusSummer visitorRare21–28 cmRegularly Jan–Oct · 0.00% in Sep
Magnolia WarblerSetophaga magnoliaPassage migrantRare11–13 cmRegularly May–Oct · 0.00% in Sep
VeeryCatharus fuscescensSummer visitorRare16–19 cmRegularly May–Sep · 0.00% in Sep
Purple MartinProgne subisSummer visitorRare18–20 cmRegularly May–Sep · 0.00% in Sep
Yellow-bellied SapsuckerSphyrapicus variusWinter visitorRare19–22 cmRegularly Sep–Mar · 0.00% in Sep
Blackpoll WarblerSetophaga striataPassage migrantRare13–15 cmRegularly May–Sep · 0.00% in Sep
Black-throated Blue WarblerSetophaga caerulescensPassage migrantRare11–13 cmRegularly May–Dec · 0.00% in Sep
Piping PloverCharadrius melodusSummer visitorRare17–18 cmRegularly Apr–Sep · 0.00% in Sep
Bay-breasted WarblerSetophaga castaneaPassage migrantRare14–14 cmRegularly May–Nov · 0.00% in Sep
Black-throated Green WarblerSetophaga virensPassage migrantRare11–12 cmRegularly May–Oct · 0.00% in Sep
Mourning WarblerGeothlypis philadelphiaPassage migrantRare10–15 cmRegularly May–Sep · 0.00% in Sep
Greylag GooseAnser anserWinter visitorRare75–90 cmRecorded all year · 0.00% in Sep
Scarlet TanagerPiranga olivaceaPassage migrantRare16–19 cmRegularly May–Sep · 0.00% in Sep
Flammulated OwlPsiloscops flammeolusSummer visitorRare15–17 cmRegularly May–Sep · 0.00% in Sep
Ruby-throated HummingbirdArchilochus colubrisPassage migrantRare7–9 cmRegularly May–Oct · 0.00% in Sep
Grey PhalaropePhalaropus fulicariusResidentRare20–22 cmRegularly Sep–Nov · 0.00% in Sep
Mute SwanCygnus olorWinter visitorRare140–160 cmRecorded all year · 0.00% in Sep
Acorn WoodpeckerMelanerpes formicivorusSummer visitorRare20–24 cmRegularly May–Feb · 0.00% in Sep
Swan GooseAnser cygnoidesWinter visitorRare81–94 cmRecorded all year · 0.00% in Sep
Muscovy DuckCairina moschataSummer visitorRare66–84 cmRegularly Jan–Nov · 0.00% in Sep
Alder FlycatcherEmpidonax alnorumPassage migrantRare13–17 cmRegularly May–Sep · 0.00% in Sep
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