WhenToBird

Spinus pinus · Fringillidae

When Do Pine Siskins Arrive in Colorado?

Adult Pine Siskin
Photo: Dominique Bérubé, CC0 1.0 via iNaturalist

Pine Siskins are in Colorado all year, but most are here in summer: numbers build from early May, peak in mid July (13% of checklists), and fall back by mid August. In the quietest week (late November) they are still on about 4.2% of checklists.

When to look

Numbers buildMay 1-7early May
PeakJul 15-21mid July
Fall back byAug 15-21mid August
FewestNov 22-30late November

Best: mid July. Here all year; numbers build from early May and fall back by mid August. Peak: on about 13% of Colorado checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Sepcommon
  10. Octcommon
  11. Novuncommon
  12. Deccommon

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

0%5%10%15%Jan 1-7: 5.8% of 32254 checklistsJan 8-14: 6.1% of 23278 checklistsJan 15-21: 5.8% of 22933 checklistsJan 22-31: 6.0% of 30856 checklistsFeb 1-7: 6.7% of 21464 checklistsFeb 8-14: 7.4% of 22910 checklistsFeb 15-21: 8.9% of 28739 checklistsFeb 22-28: 7.7% of 21833 checklistsMar 1-7: 7.9% of 23066 checklistsMar 8-14: 7.8% of 23783 checklistsMar 15-21: 8.1% of 24797 checklistsMar 22-31: 7.7% of 38439 checklistsApr 1-7: 7.1% of 31676 checklistsApr 8-14: 7.3% of 35092 checklistsApr 15-21: 7.2% of 36778 checklistsApr 22-30: 7.6% of 50885 checklistsMay 1-7: 9.6% of 44186 checklistsMay 8-14: 11% of 49011 checklistsMay 15-21: 11% of 40784 checklistsMay 22-31: 11% of 53073 checklistsJun 1-7: 11% of 32432 checklistsJun 8-14: 9.9% of 29978 checklistsJun 15-21: 10% of 29457 checklistsJun 22-30: 10% of 36072 checklistsJul 1-7: 12% of 28857 checklistsJul 8-14: 13% of 27224 checklistsJul 15-21: 13% of 27629 checklistsJul 22-31: 12% of 37318 checklistsAug 1-7: 12% of 25893 checklistsAug 8-14: 11% of 24870 checklistsAug 15-21: 9.3% of 24035 checklistsAug 22-31: 8.4% of 35691 checklistsSep 1-7: 8.0% of 27068 checklistsSep 8-14: 7.6% of 26709 checklistsSep 15-21: 7.6% of 26098 checklistsSep 22-30: 7.0% of 31550 checklistsOct 1-7: 7.1% of 24110 checklistsOct 8-14: 5.6% of 23352 checklistsOct 15-21: 5.0% of 21895 checklistsOct 22-31: 5.1% of 28319 checklistsNov 1-7: 4.2% of 21698 checklistsNov 8-14: 4.2% of 21061 checklistsNov 15-21: 4.1% of 19855 checklistsNov 22-30: 4.4% of 25798 checklistsDec 1-7: 3.9% of 18626 checklistsDec 8-14: 5.0% of 19004 checklistsDec 15-21: 5.0% of 23103 checklistsDec 22-31: 5.4% 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. San Juan CountyBest early April · 15 checklists that week, 2,012 in all55%
  2. Clear Creek CountyBest the second week of May · 135 checklists that week, 8,581 in all49%
  3. San Miguel CountyBest early June · 190 checklists that week, 8,094 in all49%
  4. Pitkin CountyBest mid March · 275 checklists that week, 15,513 in all47%
  5. Elbert CountyBest mid December · 53 checklists that week, 5,660 in all40%
  6. Dolores CountyBest early November · 27 checklists that week, 2,000 in all39%

Best spots

Share of checklists at the peak
  1. NorwoodSan Miguel County, best late February · 28 checklists that week, 1,247 in all99%
  2. Box CanyonOuray County, best mid August · 33 checklists that week, 833 in all94%
  3. Lake QuiviraClear Creek County, best late May · 31 checklists that week, 1,149 in all88%
  4. AllensparkBoulder County, best late July · 25 checklists that week, 466 in all84%
  5. Flying J Ranch ParkJefferson County, best early June · 27 checklists that week, 542 in all78%

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

Best time of day

In Colorado, the Pine Siskin is most often listed on checklists started between 6 and 8 am (13% of those checklists).

0%5%10%15%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: 12% of 71991 checklists7 am: 13% of 159189 checklists8 am: 10% of 177206 checklists9 am: 8.7% of 165269 checklists10 am: 7.5% of 141029 checklists11 am: 6.8% of 115283 checklists12 pm: 6.4% of 96068 checklists1 pm: 6.4% of 89512 checklists2 pm: 6.0% of 86319 checklists3 pm: 5.8% of 82496 checklists4 pm: 5.9% of 71648 checklists5 pm: 6.4% of 52445 checklists6 pm: 6.2% 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
January5.8%6.1%5.8%6.0%
February6.7%7.4%8.9%7.7%
March7.9%7.8%8.1%7.7%
April7.1%7.3%7.2%7.6%
May9.6%11%11%11%
June11%9.9%10%10%
July12%13%13%12%
August12%11%9.3%8.4%
September8.0%7.6%7.6%7.0%
October7.1%5.6%5.0%5.1%
November4.2%4.2%4.1%4.4%
December3.9%5.0%5.0%5.4%

Neighboring states

  • Wyoming: arrives early May, in the same week than Colorado
  • New Mexico: year-round, peaks early May
  • Utah: arrives late April, 1 week earlier than Colorado
  • Nebraska: arrives early September, 16 weeks later than Colorado

Common questions

When do Pine Siskins arrive in Colorado?
Pine Siskins are in Colorado all year, but most are here in summer: numbers build from early May, peak in mid July (13% of checklists), and fall back by mid August. In the quietest week (late November) they are still on about 4.2% of checklists.
When do Pine Siskins leave Colorado?
Pine Siskins never fully leave Colorado: numbers fall back below half their usual rate by mid August, but some are still reported in every week, about 4.2% of checklists at the low.
When is the best time to see a Pine Siskin in Colorado?
The Pine Siskin is reported most often in mid July, on about 13% of Colorado checklists.
Where in Colorado are Pine Siskins seen most often?
By county, San Juan County, Clear Creek County, and San Miguel County have the highest peak reporting rates for the Pine Siskin (counties with at least 200 checklists).