WhenToBird

Corthylio calendula · Regulidae

When Do Ruby-crowned Kinglets Arrive in Colorado?

Adult male Ruby-crowned Kinglet
Photo: Jonathan Eisen, CC BY 4.0 via iNaturalist

Ruby-crowned Kinglets are winter birds in Colorado: the first arrive in early April, they are common by mid April, peak in early October (10% of checklists), and most are gone by late November.

When to look

First arrivalsApr 1-7early April
Common byApr 15-21mid April
PeakOct 1-7early October
Most gone byNov 22-30late November

Best: early October. First arrivals early April; most are gone by late November. Peak: on about 10% of Colorado checklists.

  1. Januncommon
  2. Febrare
  3. Marrare
  4. Aprcommon
  5. Maycommon
  6. Junpeak season
  7. Julpeak season
  8. Auguncommon
  9. Seppeak season
  10. Octpeak season
  11. Novuncommon
  12. Decuncommon

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

0%5%10%15%Jan 1-7: 2.4% of 32254 checklistsJan 8-14: 1.9% of 23278 checklistsJan 15-21: 1.9% of 22933 checklistsJan 22-31: 1.7% of 30856 checklistsFeb 1-7: 1.2% of 21464 checklistsFeb 8-14: 1.1% of 22910 checklistsFeb 15-21: 0.8% of 28739 checklistsFeb 22-28: 0.7% of 21833 checklistsMar 1-7: 0.8% of 23066 checklistsMar 8-14: 0.7% of 23783 checklistsMar 15-21: 0.7% of 24797 checklistsMar 22-31: 0.8% of 38439 checklistsApr 1-7: 1.3% of 31676 checklistsApr 8-14: 2.1% of 35092 checklistsApr 15-21: 3.9% of 36778 checklistsApr 22-30: 5.7% of 50885 checklistsMay 1-7: 5.4% of 44186 checklistsMay 8-14: 4.9% of 49011 checklistsMay 15-21: 5.1% of 40784 checklistsMay 22-31: 6.1% of 53073 checklistsJun 1-7: 8.2% of 32432 checklistsJun 8-14: 9.3% of 29978 checklistsJun 15-21: 10% of 29457 checklistsJun 22-30: 9.8% of 36072 checklistsJul 1-7: 9.5% of 28857 checklistsJul 8-14: 8.9% of 27224 checklistsJul 15-21: 5.9% of 27629 checklistsJul 22-31: 3.9% of 37318 checklistsAug 1-7: 3.0% of 25893 checklistsAug 8-14: 2.6% of 24870 checklistsAug 15-21: 2.5% of 24035 checklistsAug 22-31: 3.0% of 35691 checklistsSep 1-7: 3.8% of 27068 checklistsSep 8-14: 4.6% of 26709 checklistsSep 15-21: 6.1% of 26098 checklistsSep 22-30: 9.2% of 31550 checklistsOct 1-7: 11% of 24110 checklistsOct 8-14: 10% of 23352 checklistsOct 15-21: 8.7% of 21895 checklistsOct 22-31: 5.6% of 28319 checklistsNov 1-7: 2.9% of 21698 checklistsNov 8-14: 2.3% of 21061 checklistsNov 15-21: 3.2% of 19855 checklistsNov 22-30: 2.6% of 25798 checklistsDec 1-7: 2.3% of 18626 checklistsDec 8-14: 2.4% of 19004 checklistsDec 15-21: 2.4% of 23103 checklistsDec 22-31: 1.9% 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. Hinsdale CountyBest the second week of June · 144 checklists that week, 2,303 in all49%
  2. Gilpin CountyBest early June · 170 checklists that week, 4,252 in all49%
  3. San Juan CountyBest mid June · 103 checklists that week, 2,012 in all46%
  4. Pitkin CountyBest the second week of May · 360 checklists that week, 15,513 in all45%
  5. Clear Creek CountyBest mid June · 288 checklists that week, 8,581 in all44%
  6. Mineral CountyBest the second week of May · 41 checklists that week, 1,750 in all39%

Best spots

Share of checklists at the peak
  1. Hallam LakePitkin County, best early May · 32 checklists that week, 1,206 in all95%
  2. Brainard LakeBoulder County, best mid June · 21 checklists that week, 512 in all95%
  3. Mud Lake (Delonde Creek)Boulder County, best the second week of June · 22 checklists that week, 346 in all89%
  4. Casto CreekJefferson County, best the second week of June · 71 checklists that week, 1,275 in all89%
  5. Flying J Ranch ParkJefferson County, best early June · 27 checklists that week, 542 in all84%
  6. Pike National ForestEl Paso County, best mid June · 20 checklists that week, 434 in all83%

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

Best time of day

In Colorado, the Ruby-crowned Kinglet is most often listed on checklists started between 8 and 10 am (5.5% of those checklists).

0%2%4%6%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: 5.3% of 71991 checklists7 am: 5.3% of 159189 checklists8 am: 5.5% of 177206 checklists9 am: 5.5% of 165269 checklists10 am: 4.8% of 141029 checklists11 am: 4.4% of 115283 checklists12 pm: 3.9% of 96068 checklists1 pm: 3.7% of 89512 checklists2 pm: 3.4% of 86319 checklists3 pm: 3.1% of 82496 checklists4 pm: 3.0% of 71648 checklists5 pm: 3.2% of 52445 checklists6 pm: 2.7% 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
January2.4%1.9%1.9%1.7%
February1.2%1.1%0.8%0.7%
March0.8%0.7%0.7%0.8%
April1.3%2.1%3.9%5.7%
May5.4%4.9%5.1%6.1%
June8.2%9.3%10%9.8%
July9.5%8.9%5.9%3.9%
August3.0%2.6%2.5%3.0%
September3.8%4.6%6.1%9.2%
October11%10%8.7%5.6%
November2.9%2.3%3.2%2.6%
December2.3%2.4%2.4%1.9%

Neighboring states

  • Wyoming: arrives the second week of April, 1 week later than Colorado
  • New Mexico: arrives early September, 20 weeks later than Colorado
  • Utah: arrives late September, 23 weeks later than Colorado
  • Nebraska: arrives early September, 20 weeks later than Colorado

Common questions

When do Ruby-crowned Kinglets arrive in Colorado?
Ruby-crowned Kinglets are winter birds in Colorado: the first arrive in early April, they are common by mid April, peak in early October (10% of checklists), and most are gone by late November.
When do Ruby-crowned Kinglets leave Colorado?
Most Ruby-crowned Kinglets have left Colorado by late November, when reports fall below half their usual rate. Stragglers are still reported until the second week of February.
When is the best time to see a Ruby-crowned Kinglet in Colorado?
The Ruby-crowned Kinglet is reported most often in early October, on about 10% of Colorado checklists.
Where in Colorado are Ruby-crowned Kinglets seen most often?
By county, Hinsdale County, Gilpin County, and San Juan County have the highest peak reporting rates for the Ruby-crowned Kinglet (counties with at least 200 checklists).