WhenToBird

Clangula hyemalis · Anatidae

When Do Long-tailed Ducks Arrive in Colorado?

Adult male Long-tailed Duck
Photo: Diego González Dopico, CC BY 4.0 via iNaturalist

Long-tailed Ducks are winter birds in Colorado: they arrive in the second week of November, peak in the second week of December (1.2% of checklists), and most are gone by early February.

When to look

First arrivalsNov 8-14the second week of November
Common byNov 8-14the second week of November
PeakDec 8-14the second week of December
Most gone byFeb 1-7early February

Best: the second week of December. First arrivals the second week of November; most are gone by early February. Peak: on about 1.2% of Colorado checklists.

  1. Janpeak season
  2. Febuncommon
  3. Maruncommon
  4. Apruncommon
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octrare
  11. Novcommon
  12. Decpeak season

Darker months: more checklists report it. Outlined: peak month.

0%0.5%1%1.5%Jan 1-7: 1.3% of 32254 checklistsJan 8-14: 0.8% of 23278 checklistsJan 15-21: 0.8% of 22933 checklistsJan 22-31: 0.7% of 30856 checklistsFeb 1-7: 0.3% of 21464 checklistsFeb 8-14: 0.2% of 22910 checklistsFeb 15-21: 0.5% of 28739 checklistsFeb 22-28: 0.4% of 21833 checklistsMar 1-7: 0.4% of 23066 checklistsMar 8-14: 0.3% of 23783 checklistsMar 15-21: 0.2% of 24797 checklistsMar 22-31: 0.2% of 38439 checklistsApr 1-7: 0.2% of 31676 checklistsApr 8-14: 0.2% of 35092 checklistsApr 15-21: 0.2% of 36778 checklistsApr 22-30: 0.1% of 50885 checklistsMay 1-7: 0.1% of 44186 checklistsMay 8-14: 0.1% of 49011 checklistsMay 15-21: 0.1% of 40784 checklistsMay 22-31: 0.1% of 53073 checklistsJun 1-7: 0.1% of 32432 checklistsJun 8-14: 0.1% of 29978 checklistsJun 15-21: 0.1% of 29457 checklistsJun 22-30: 0.1% of 36072 checklistsJul 1-7: 0.1% of 28857 checklistsJul 8-14: 0.1% of 27224 checklistsJul 15-21: 0.1% of 27629 checklistsJul 22-31: 0.1% of 37318 checklistsAug 1-7: 0% of 25893 checklistsAug 8-14: 0.1% of 24870 checklistsAug 15-21: 0.1% of 24035 checklistsAug 22-31: 0.1% of 35691 checklistsSep 1-7: 0.1% of 27068 checklistsSep 8-14: 0.1% of 26709 checklistsSep 15-21: 0.1% of 26098 checklistsSep 22-30: 0.1% of 31550 checklistsOct 1-7: 0% of 24110 checklistsOct 8-14: 0% of 23352 checklistsOct 15-21: 0.1% of 21895 checklistsOct 22-31: 0.1% of 28319 checklistsNov 1-7: 0.2% of 21698 checklistsNov 8-14: 0.5% of 21061 checklistsNov 15-21: 0.5% of 19855 checklistsNov 22-30: 0.7% of 25798 checklistsDec 1-7: 1.3% of 18626 checklistsDec 8-14: 1.3% of 19004 checklistsDec 15-21: 1.1% of 23103 checklistsDec 22-31: 0.9% of 30802 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.

Frequency is the share of complete checklists in Colorado that listed the bird, 2016–2025. It is not a head count, and it follows where and when people go birding. How to read it.

JanFebMarAprMayJunJulAugSepOctNovDec
today
Second week of November

Each county is shaded by the share of complete checklists there that listed the bird, blended with the weeks either side. Darker is more often. It follows where people watch birds, not how many birds there are. How to read it.

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Where in Colorado

Best counties

Share of checklists at the peak
  1. Weld CountyBest the second week of December · 630 checklists that week, 40,146 in all10%
  2. Crowley CountyBest late November · 20 checklists that week, 1,883 in all9.4%
  3. Costilla CountyBest late April · 40 checklists that week, 1,323 in all8.7%
  4. Lake CountyBest late November · 12 checklists that week, 2,361 in all4.5%
  5. Bent CountyBest late November · 43 checklists that week, 5,275 in all4.4%
  6. Garfield CountyBest early February · 201 checklists that week, 12,156 in all3.8%

Best spots

Share of checklists at the peak
  1. South Platte Pk\ Carson Nature Area (Columbine Hills)Jefferson County, best mid December · 79 checklists that week, 1,365 in all54%
  2. South Platte Pk\ Carson Nature Area (South Platte Reservoir)Arapahoe County, best the second week of December · 58 checklists that week, 2,027 in all49%
  3. Carbon Valley Recreation District Regional (Metro District) ParksWeld County, best the second week of December · 71 checklists that week, 994 in all48%
  4. Bowles Reservoir Number OneDenver County, best late December · 34 checklists that week, 411 in all43%
  5. Carter Lake ReservoirLarimer County, best late January · 29 checklists that week, 362 in all43%
  6. Cattail PondLarimer County, best the second week of March · 23 checklists that week, 866 in all36%

Busy spots report more of everything; compare the checklist counts before you drive anywhere.

Best time of day

In Colorado, the Long-tailed Duck is most often listed on checklists started between 12 and 2 pm (0.4% of those checklists).

0%0.5%12 am: too few checklists (512) to judge1 am: too few checklists (468) to judge2 am: too few checklists (513) to judge3 am: too few checklists (656) to judge4 am: too few checklists (1918) to judge5 am: too few checklists (16045) to judge6 am: 0.1% of 71991 checklists7 am: 0.1% of 159189 checklists8 am: 0.2% of 177206 checklists9 am: 0.3% of 165269 checklists10 am: 0.3% of 141029 checklists11 am: 0.4% of 115283 checklists12 pm: 0.4% of 96068 checklists1 pm: 0.4% of 89512 checklists2 pm: 0.3% of 86319 checklists3 pm: 0.3% of 82496 checklists4 pm: 0.2% of 71648 checklists5 pm: 0.1% of 52445 checklists6 pm: 0.1% of 40199 checklists7 pm: too few checklists (24246) to judge8 pm: too few checklists (7986) to judge9 pm: too few checklists (2004) to judge10 pm: too few checklists (888) to judge11 pm: too few checklists (450) to judge12a3a6a9a12p3p6p9p
Share of checklists started in each local hour that reported it. It reflects when people go birding as well as when birds are active. Grey hours have too few checklists (under 2% of the state’s, or under 200) to judge.
Week-by-week table
MonthDays 1-78-1415-2122-end
January1.3%0.8%0.8%0.7%
February0.3%0.2%0.5%0.4%
March0.4%0.3%0.2%0.2%
April0.2%0.2%0.2%0.1%
May0.1%0.1%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0%0.1%0.1%0.1%
September0.1%0.1%0.1%0.1%
October0%0%0.1%0.1%
November0.2%0.5%0.5%0.7%
December1.3%1.3%1.1%0.9%

Neighboring states

  • Wyoming: arrives early November, 1 week earlier than Colorado
  • Nebraska: arrives late October, 2 weeks earlier than Colorado
  • South Dakota: arrives mid November, 1 week later than Colorado
  • Kansas: arrives mid November, 1 week later than Colorado

Common questions

When do Long-tailed Ducks arrive in Colorado?
Long-tailed Ducks are winter birds in Colorado: they arrive in the second week of November, peak in the second week of December (1.2% of checklists), and most are gone by early February.
When do Long-tailed Ducks leave Colorado?
Most Long-tailed Ducks have left Colorado by early February, when reports fall below half their usual rate.
When is the best time to see a Long-tailed Duck in Colorado?
The Long-tailed Duck is reported most often in the second week of December, on about 1.2% of Colorado checklists.
Where in Colorado are Long-tailed Ducks seen most often?
By county, Weld County, Crowley County, and Costilla County have the highest peak reporting rates for the Long-tailed Duck (counties with at least 200 checklists).