WhenToBird

Haliaeetus leucocephalus · Accipitridae

When Do Bald Eagles Arrive in Colorado?

Adult Bald Eagle
Photo: Marcel_Pepin, CC BY 4.0 via iNaturalist

Bald Eagles are in Colorado all year, but most are here in winter: numbers build from late October, peak in early January (13% of checklists), and fall back by late April. In the quietest week (the second week of July) they are still on about 2.3% of checklists.

When to look

Numbers buildOct 22-31late October
PeakJan 1-7early January
Fall back byApr 22-30late April
FewestJul 8-14the second week of July

Best: early January. Here all year; numbers build from late October and fall back by late April. Peak: on about 13% of Colorado checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Maycommon
  6. Jununcommon
  7. Juluncommon
  8. Auguncommon
  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: 13% of 32254 checklistsJan 8-14: 13% of 23278 checklistsJan 15-21: 12% of 22933 checklistsJan 22-31: 12% of 30856 checklistsFeb 1-7: 12% of 21464 checklistsFeb 8-14: 11% of 22910 checklistsFeb 15-21: 9.8% of 28739 checklistsFeb 22-28: 12% of 21833 checklistsMar 1-7: 11% of 23066 checklistsMar 8-14: 10% of 23783 checklistsMar 15-21: 10% of 24797 checklistsMar 22-31: 9.8% of 38439 checklistsApr 1-7: 9.3% of 31676 checklistsApr 8-14: 9.1% of 35092 checklistsApr 15-21: 10% of 36778 checklistsApr 22-30: 9.0% of 50885 checklistsMay 1-7: 7.4% of 44186 checklistsMay 8-14: 5.9% of 49011 checklistsMay 15-21: 5.4% of 40784 checklistsMay 22-31: 4.5% of 53073 checklistsJun 1-7: 3.6% of 32432 checklistsJun 8-14: 2.6% of 29978 checklistsJun 15-21: 2.7% of 29457 checklistsJun 22-30: 2.5% of 36072 checklistsJul 1-7: 2.3% of 28857 checklistsJul 8-14: 2.0% of 27224 checklistsJul 15-21: 2.5% of 27629 checklistsJul 22-31: 2.5% of 37318 checklistsAug 1-7: 3.1% of 25893 checklistsAug 8-14: 3.6% of 24870 checklistsAug 15-21: 3.6% of 24035 checklistsAug 22-31: 4.3% of 35691 checklistsSep 1-7: 4.5% of 27068 checklistsSep 8-14: 5.2% of 26709 checklistsSep 15-21: 4.7% of 26098 checklistsSep 22-30: 4.9% of 31550 checklistsOct 1-7: 5.2% of 24110 checklistsOct 8-14: 6.2% of 23352 checklistsOct 15-21: 6.5% of 21895 checklistsOct 22-31: 7.8% of 28319 checklistsNov 1-7: 8.4% of 21698 checklistsNov 8-14: 9.6% of 21061 checklistsNov 15-21: 9.3% of 19855 checklistsNov 22-30: 11% of 25798 checklistsDec 1-7: 12% of 18626 checklistsDec 8-14: 12% of 19004 checklistsDec 15-21: 12% of 23103 checklistsDec 22-31: 13% 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. Washington CountyBest mid February · 19 checklists that week, 2,511 in all55%
  2. Bent CountyBest early January · 50 checklists that week, 5,275 in all44%
  3. Adams CountyBest mid January · 785 checklists that week, 44,639 in all43%
  4. Kiowa CountyBest early February · 32 checklists that week, 3,854 in all43%
  5. Sedgwick CountyBest mid December · 11 checklists that week, 1,168 in all39%
  6. Morgan CountyBest late February · 82 checklists that week, 5,181 in all37%

Best spots

Share of checklists at the peak
  1. Colorado River Segment 7Eagle County, best late April · 23 checklists that week, 499 in all92%
  2. Wrights ReservoirTeller County, best mid May · 23 checklists that week, 431 in all87%
  3. Barr Lake (northwest)Adams County, best the second week of December · 40 checklists that week, 2,694 in all86%
  4. Barr LakeAdams County, best early January · 48 checklists that week, 2,800 in all86%
  5. Rocky Mountain Arsenal National Wildlife Refuge (east)Adams County, best early January · 24 checklists that week, 560 in all85%
  6. Fossil Creek Reservoir Natural AreaLarimer County, best the second week of January · 20 checklists that week, 1,582 in all84%

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

Best time of day

In Colorado, the Bald Eagle is most often listed on checklists started between 1 and 3 pm (8.6% 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: 5.0% of 71991 checklists7 am: 6.2% of 159189 checklists8 am: 7.4% of 177206 checklists9 am: 8.2% of 165269 checklists10 am: 8.5% of 141029 checklists11 am: 8.6% of 115283 checklists12 pm: 8.2% of 96068 checklists1 pm: 8.5% of 89512 checklists2 pm: 8.8% of 86319 checklists3 pm: 8.0% of 82496 checklists4 pm: 6.8% of 71648 checklists5 pm: 5.7% of 52445 checklists6 pm: 4.2% 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
January13%13%12%12%
February12%11%9.8%12%
March11%10%10%9.8%
April9.3%9.1%10%9.0%
May7.4%5.9%5.4%4.5%
June3.6%2.6%2.7%2.5%
July2.3%2.0%2.5%2.5%
August3.1%3.6%3.6%4.3%
September4.5%5.2%4.7%4.9%
October5.2%6.2%6.5%7.8%
November8.4%9.6%9.3%11%
December12%12%12%13%

Neighboring states

  • Wyoming: year-round, peaks mid December
  • New Mexico: arrives early November, 1 week later than Colorado
  • Utah: arrives mid July, 13 weeks earlier than Colorado
  • Nebraska: arrives the second week of November, 2 weeks later than Colorado

Common questions

When do Bald Eagles arrive in Colorado?
Bald Eagles are in Colorado all year, but most are here in winter: numbers build from late October, peak in early January (13% of checklists), and fall back by late April. In the quietest week (the second week of July) they are still on about 2.3% of checklists.
When do Bald Eagles leave Colorado?
Bald Eagles never fully leave Colorado: numbers fall back below half their usual rate by late April, but some are still reported in every week, about 2.3% of checklists at the low.
When is the best time to see a Bald Eagle in Colorado?
The Bald Eagle is reported most often in early January, on about 13% of Colorado checklists.
Where in Colorado are Bald Eagles seen most often?
By county, Washington County, Bent County, and Adams County have the highest peak reporting rates for the Bald Eagle (counties with at least 200 checklists).