WhenToBird

Bucephala islandica · Anatidae

When Do Barrow's Goldeneyes Arrive in Colorado?

Adult male Barrow's Goldeneye
Photo: Kevin Krebs, CC BY 4.0 via iNaturalist

Barrow's Goldeneyes are winter birds in Colorado: they arrive in early November, peak in the second week of January (1.4% of checklists), and most are gone by early April.

When to look

First arrivalsNov 1-7early November
Common byNov 1-7early November
PeakJan 8-14the second week of January
Most gone byApr 1-7early April

Best: the second week of January. First arrivals early November; most are gone by early April. Peak: on about 1.4% of Colorado checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Aprcommon
  5. Mayrare
  6. Junrare
  7. Julrare
  8. Augrare
  9. Seprare
  10. Octuncommon
  11. Novpeak season
  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: 1.5% of 23278 checklistsJan 15-21: 1.3% of 22933 checklistsJan 22-31: 1.3% of 30856 checklistsFeb 1-7: 1.0% of 21464 checklistsFeb 8-14: 1.1% of 22910 checklistsFeb 15-21: 0.9% of 28739 checklistsFeb 22-28: 0.9% of 21833 checklistsMar 1-7: 0.7% of 23066 checklistsMar 8-14: 0.9% of 23783 checklistsMar 15-21: 0.7% of 24797 checklistsMar 22-31: 0.7% of 38439 checklistsApr 1-7: 0.5% of 31676 checklistsApr 8-14: 0.4% of 35092 checklistsApr 15-21: 0.3% 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: 0.2% of 37318 checklistsAug 1-7: 0.2% 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: 0.1% of 24110 checklistsOct 8-14: 0.1% of 23352 checklistsOct 15-21: 0.1% of 21895 checklistsOct 22-31: 0.2% of 28319 checklistsNov 1-7: 0.5% of 21698 checklistsNov 8-14: 0.9% of 21061 checklistsNov 15-21: 1.1% of 19855 checklistsNov 22-30: 1.1% of 25798 checklistsDec 1-7: 1.2% of 18626 checklistsDec 8-14: 1.1% of 19004 checklistsDec 15-21: 0.8% of 23103 checklistsDec 22-31: 1.1% 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. Summit CountyBest the second week of January · 156 checklists that week, 14,176 in all27%
  2. Routt CountyBest the second week of November · 79 checklists that week, 10,504 in all19%
  3. Chaffee CountyBest late December · 187 checklists that week, 14,510 in all18%
  4. Grand CountyBest early December · 36 checklists that week, 11,286 in all18%
  5. Gunnison CountyBest early December · 22 checklists that week, 9,894 in all11%
  6. Garfield CountyBest mid January · 229 checklists that week, 12,156 in all11%

Best spots

Share of checklists at the peak
  1. Sands Lake State Wildlife AreaChaffee County, best early December · 23 checklists that week, 1,345 in all90%
  2. Blue River Ranch LakesSummit County, best late March · 22 checklists that week, 154 in all81%
  3. Overland Pond ParkDenver County, best the second week of January · 41 checklists that week, 1,033 in all80%
  4. Windy Gap ReservoirGrand County, best late April · 26 checklists that week, 536 in all70%
  5. Lake CatamountRoutt County, best late October · 22 checklists that week, 224 in all69%

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

Best time of day

In Colorado, the Barrow's Goldeneye is most often listed on checklists started between 1 and 3 pm (0.7% of those checklists).

0%0.5%1%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: 0.2% of 71991 checklists7 am: 0.2% of 159189 checklists8 am: 0.3% of 177206 checklists9 am: 0.5% of 165269 checklists10 am: 0.5% of 141029 checklists11 am: 0.6% of 115283 checklists12 pm: 0.7% of 96068 checklists1 pm: 0.7% of 89512 checklists2 pm: 0.7% of 86319 checklists3 pm: 0.5% of 82496 checklists4 pm: 0.4% of 71648 checklists5 pm: 0.2% 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%1.5%1.3%1.3%
February1.0%1.1%0.9%0.9%
March0.7%0.9%0.7%0.7%
April0.5%0.4%0.3%0.1%
May0.1%0.1%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.2%
August0.2%0.1%0.1%0.1%
September0.1%0.1%0.1%0.1%
October0.1%0.1%0.1%0.2%
November0.5%0.9%1.1%1.1%
December1.2%1.1%0.8%1.1%

Neighboring states

  • Wyoming: year-round, peaks the second week of November
  • Utah: arrives the second week of November, 1 week later than Colorado
  • Montana: arrives the second week of October, 3 weeks earlier than Colorado
  • Idaho: arrives late October, 1 week earlier than Colorado

Common questions

When do Barrow's Goldeneyes arrive in Colorado?
Barrow's Goldeneyes are winter birds in Colorado: they arrive in early November, peak in the second week of January (1.4% of checklists), and most are gone by early April.
When do Barrow's Goldeneyes leave Colorado?
Most Barrow's Goldeneyes have left Colorado by early April, when reports fall below half their usual rate.
When is the best time to see a Barrow's Goldeneye in Colorado?
The Barrow's Goldeneye is reported most often in the second week of January, on about 1.4% of Colorado checklists.
Where in Colorado are Barrow's Goldeneyes seen most often?
By county, Summit County, Routt County, and Chaffee County have the highest peak reporting rates for the Barrow's Goldeneye (counties with at least 200 checklists).