WhenToBird

Podiceps nigricollis · Podicipedidae

When Do Eared Grebes Arrive in Colorado?

Adult Eared Grebe
Photo: Сергей Неклюдов, CC BY 4.0 via iNaturalist

Eared Grebes reach Colorado in mid March, are common by late March, peak in late April (6.2% of checklists), and most are gone by the second week of June.

When to look

First arrivalsMar 15-21mid March
Common byMar 22-31late March
PeakApr 22-30late April
Most gone byJun 8-14the second week of June

Best: late April. First arrivals mid March; most are gone by the second week of June. Peak: on about 6.2% of Colorado checklists.

  1. Janrare
  2. Febrare
  3. Maruncommon
  4. Aprpeak season
  5. Maypeak season
  6. Jununcommon
  7. Juluncommon
  8. Auguncommon
  9. Sepuncommon
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%2%4%6%8%Jan 1-7: 0.8% of 32254 checklistsJan 8-14: 0.4% of 23278 checklistsJan 15-21: 0.3% of 22933 checklistsJan 22-31: 0.4% of 30856 checklistsFeb 1-7: 0.1% of 21464 checklistsFeb 8-14: 0.2% of 22910 checklistsFeb 15-21: 0.2% of 28739 checklistsFeb 22-28: 0.1% of 21833 checklistsMar 1-7: 0.2% of 23066 checklistsMar 8-14: 0.4% of 23783 checklistsMar 15-21: 0.8% of 24797 checklistsMar 22-31: 1.6% of 38439 checklistsApr 1-7: 1.8% of 31676 checklistsApr 8-14: 3.2% of 35092 checklistsApr 15-21: 5.9% of 36778 checklistsApr 22-30: 6.9% of 50885 checklistsMay 1-7: 5.6% of 44186 checklistsMay 8-14: 3.4% of 49011 checklistsMay 15-21: 2.3% of 40784 checklistsMay 22-31: 1.9% of 53073 checklistsJun 1-7: 1.6% of 32432 checklistsJun 8-14: 1.0% of 29978 checklistsJun 15-21: 0.9% of 29457 checklistsJun 22-30: 0.9% of 36072 checklistsJul 1-7: 0.9% of 28857 checklistsJul 8-14: 0.8% of 27224 checklistsJul 15-21: 0.9% of 27629 checklistsJul 22-31: 1.2% of 37318 checklistsAug 1-7: 1.1% of 25893 checklistsAug 8-14: 1.3% of 24870 checklistsAug 15-21: 1.2% of 24035 checklistsAug 22-31: 1.3% of 35691 checklistsSep 1-7: 1.4% of 27068 checklistsSep 8-14: 2.0% of 26709 checklistsSep 15-21: 1.9% of 26098 checklistsSep 22-30: 2.4% of 31550 checklistsOct 1-7: 2.3% of 24110 checklistsOct 8-14: 3.0% of 23352 checklistsOct 15-21: 3.6% of 21895 checklistsOct 22-31: 5.7% of 28319 checklistsNov 1-7: 6.4% of 21698 checklistsNov 8-14: 6.0% of 21061 checklistsNov 15-21: 3.9% of 19855 checklistsNov 22-30: 3.5% of 25798 checklistsDec 1-7: 2.4% of 18626 checklistsDec 8-14: 1.1% of 19004 checklistsDec 15-21: 0.6% of 23103 checklistsDec 22-31: 0.5% 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. Costilla CountyBest late April · 40 checklists that week, 1,323 in all55%
  2. Crowley CountyBest mid November · 24 checklists that week, 1,883 in all36%
  3. Kiowa CountyBest the second week of November · 58 checklists that week, 3,854 in all36%
  4. Park CountyBest early November · 155 checklists that week, 11,432 in all28%
  5. Delta CountyBest late April · 318 checklists that week, 6,509 in all28%
  6. Rio Blanco CountyBest the second week of November · 51 checklists that week, 2,806 in all26%

Best spots

Share of checklists at the peak
  1. Walden ReservoirJackson County, best late June · 29 checklists that week, 546 in all96%
  2. Dan Noble State Wildlife AreaSan Miguel County, best late October · 23 checklists that week, 399 in all95%
  3. Smith ReservoirCostilla County, best early May · 20 checklists that week, 432 in all90%
  4. Rueter-Hess ReservoirDouglas County, best mid October · 20 checklists that week, 742 in all85%
  5. Case Reservoir Number 2Jackson County, best early July · 30 checklists that week, 474 in all84%
  6. Cheraw LakeOtero County, best early May · 32 checklists that week, 384 in all80%

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

Best time of day

In Colorado, the Eared Grebe is most often listed on checklists started between 11 am and 1 pm (2.6% of those checklists).

0%1%2%3%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: 1.6% of 71991 checklists7 am: 1.6% of 159189 checklists8 am: 1.9% of 177206 checklists9 am: 2.2% of 165269 checklists10 am: 2.4% of 141029 checklists11 am: 2.7% of 115283 checklists12 pm: 2.5% of 96068 checklists1 pm: 2.6% of 89512 checklists2 pm: 2.5% of 86319 checklists3 pm: 2.4% of 82496 checklists4 pm: 2.2% of 71648 checklists5 pm: 2.2% of 52445 checklists6 pm: 1.8% 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
January0.8%0.4%0.3%0.4%
February0.1%0.2%0.2%0.1%
March0.2%0.4%0.8%1.6%
April1.8%3.2%5.9%6.9%
May5.6%3.4%2.3%1.9%
June1.6%1.0%0.9%0.9%
July0.9%0.8%0.9%1.2%
August1.1%1.3%1.2%1.3%
September1.4%2.0%1.9%2.4%
October2.3%3.0%3.6%5.7%
November6.4%6.0%3.9%3.5%
December2.4%1.1%0.6%0.5%

Neighboring states

  • Wyoming: arrives early April, 2 weeks later than Colorado
  • New Mexico: arrives late August, 21 weeks later than Colorado
  • Utah: arrives early March, 2 weeks earlier than Colorado
  • Nebraska: arrives late March, 1 week later than Colorado

Common questions

When do Eared Grebes arrive in Colorado?
Eared Grebes reach Colorado in mid March, are common by late March, peak in late April (6.2% of checklists), and most are gone by the second week of June.
When do Eared Grebes leave Colorado?
Most Eared Grebes have left Colorado by the second week of June, when reports fall below half their usual rate.
When is the best time to see a Eared Grebe in Colorado?
The Eared Grebe is reported most often in late April, on about 6.2% of Colorado checklists.
Where in Colorado are Eared Grebes seen most often?
By county, Costilla County, Crowley County, and Kiowa County have the highest peak reporting rates for the Eared Grebe (counties with at least 200 checklists).