WhenToBird

Aythya collaris · Anatidae

When Do Ring-necked Ducks Arrive in Colorado?

Adult male Ring-necked Duck
Photo: Marcel_Pepin, CC BY 4.0 via iNaturalist

Ring-necked Ducks are winter birds in Colorado: the first arrive in the second week of September, they are common by the second week of October, peak in mid March (13% of checklists), and most are gone by late April.

When to look

First arrivalsSep 8-14the second week of September
Common byOct 8-14the second week of October
PeakMar 15-21mid March
Most gone byApr 22-30late April

Best: mid March. First arrivals the second week of September; most are gone by late April. Peak: on about 13% of Colorado checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Sepuncommon
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

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

0%5%10%15%Jan 1-7: 12% of 32254 checklistsJan 8-14: 12% of 23278 checklistsJan 15-21: 11% of 22933 checklistsJan 22-31: 11% of 30856 checklistsFeb 1-7: 11% of 21464 checklistsFeb 8-14: 10% of 22910 checklistsFeb 15-21: 9.2% of 28739 checklistsFeb 22-28: 12% of 21833 checklistsMar 1-7: 12% of 23066 checklistsMar 8-14: 13% of 23783 checklistsMar 15-21: 13% of 24797 checklistsMar 22-31: 13% of 38439 checklistsApr 1-7: 12% of 31676 checklistsApr 8-14: 11% of 35092 checklistsApr 15-21: 9.5% of 36778 checklistsApr 22-30: 7.1% of 50885 checklistsMay 1-7: 3.5% of 44186 checklistsMay 8-14: 2.1% of 49011 checklistsMay 15-21: 1.6% of 40784 checklistsMay 22-31: 1.3% of 53073 checklistsJun 1-7: 1.2% of 32432 checklistsJun 8-14: 1.0% of 29978 checklistsJun 15-21: 1.1% of 29457 checklistsJun 22-30: 0.9% of 36072 checklistsJul 1-7: 0.9% of 28857 checklistsJul 8-14: 0.9% of 27224 checklistsJul 15-21: 0.8% of 27629 checklistsJul 22-31: 0.7% of 37318 checklistsAug 1-7: 0.7% of 25893 checklistsAug 8-14: 0.6% of 24870 checklistsAug 15-21: 0.7% of 24035 checklistsAug 22-31: 0.7% of 35691 checklistsSep 1-7: 0.9% of 27068 checklistsSep 8-14: 1.1% of 26709 checklistsSep 15-21: 1.7% of 26098 checklistsSep 22-30: 2.7% of 31550 checklistsOct 1-7: 3.9% of 24110 checklistsOct 8-14: 5.9% of 23352 checklistsOct 15-21: 7.2% of 21895 checklistsOct 22-31: 10% of 28319 checklistsNov 1-7: 11% of 21698 checklistsNov 8-14: 12% of 21061 checklistsNov 15-21: 10% of 19855 checklistsNov 22-30: 11% of 25798 checklistsDec 1-7: 12% of 18626 checklistsDec 8-14: 10% of 19004 checklistsDec 15-21: 9.7% of 23103 checklistsDec 22-31: 11% 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.

Embed this map on your site

Where in Colorado

Best counties

Share of checklists at the peak
  1. Rio Blanco CountyBest early November · 39 checklists that week, 2,806 in all37%
  2. Phillips CountyBest late March · 15 checklists that week, 1,052 in all32%
  3. Broomfield CountyBest the second week of November · 301 checklists that week, 16,139 in all31%
  4. Costilla CountyBest late March · 38 checklists that week, 1,323 in all31%
  5. Rio Grande CountyBest the second week of April · 69 checklists that week, 4,655 in all31%
  6. Routt CountyBest the second week of November · 79 checklists that week, 10,504 in all30%

Best spots

Share of checklists at the peak
  1. Erie LakeBoulder County, best late December · 47 checklists that week, 923 in all98%
  2. Sands Lake State Wildlife AreaChaffee County, best late November · 30 checklists that week, 1,345 in all97%
  3. Pella CrossingBoulder County, best early December · 64 checklists that week, 3,697 in all97%
  4. Hodgson-Harris ReservoirBoulder County, best mid February · 23 checklists that week, 1,007 in all96%
  5. Washington Park (south)Denver County, best late December · 29 checklists that week, 823 in all96%

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

Best time of day

In Colorado, the Ring-necked Duck is most often listed on checklists started between 1 and 3 pm (8.4% of those checklists).

0%5%10%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: 2.5% of 71991 checklists7 am: 4.0% of 159189 checklists8 am: 5.7% of 177206 checklists9 am: 6.6% of 165269 checklists10 am: 7.1% of 141029 checklists11 am: 7.4% of 115283 checklists12 pm: 7.7% of 96068 checklists1 pm: 8.3% of 89512 checklists2 pm: 8.5% of 86319 checklists3 pm: 8.0% of 82496 checklists4 pm: 7.0% of 71648 checklists5 pm: 5.1% of 52445 checklists6 pm: 3.2% 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
January12%12%11%11%
February11%10%9.2%12%
March12%13%13%13%
April12%11%9.5%7.1%
May3.5%2.1%1.6%1.3%
June1.2%1.0%1.1%0.9%
July0.9%0.9%0.8%0.7%
August0.7%0.6%0.7%0.7%
September0.9%1.1%1.7%2.7%
October3.9%5.9%7.2%10%
November11%12%10%11%
December12%10%9.7%11%

Neighboring states

  • Wyoming: arrives the second week of February, 20 weeks later than Colorado
  • New Mexico: arrives late September, 2 weeks later than Colorado
  • Utah: arrives mid September, 1 week later than Colorado
  • Nebraska: arrives early October, 3 weeks later than Colorado

Common questions

When do Ring-necked Ducks arrive in Colorado?
Ring-necked Ducks are winter birds in Colorado: the first arrive in the second week of September, they are common by the second week of October, peak in mid March (13% of checklists), and most are gone by late April.
When do Ring-necked Ducks leave Colorado?
Most Ring-necked Ducks have left Colorado by late April, when reports fall below half their usual rate. Stragglers are still reported until the second week of June.
When is the best time to see a Ring-necked Duck in Colorado?
The Ring-necked Duck is reported most often in mid March, on about 13% of Colorado checklists.
Where in Colorado are Ring-necked Ducks seen most often?
By county, Rio Blanco County, Phillips County, and Broomfield County have the highest peak reporting rates for the Ring-necked Duck (counties with at least 200 checklists).