WhenToBird

Falco columbarius · Falconidae

When Do Merlins Arrive in Montana?

Adult female Merlin
Photo: Cricket Raspet, CC BY 4.0 via iNaturalist

Merlins arrive in Montana in mid August, peak in late September (4.0% of checklists), and most are gone by early March.

When to look

First arrivalsAug 15-21mid August
Common byAug 15-21mid August
PeakSep 22-30late September
Most gone byMar 1-7early March

Best: late September. First arrivals mid August; most are gone by early March. Peak: on about 4.0% of Montana checklists.

  1. Jancommon
  2. Febcommon
  3. Maruncommon
  4. Apruncommon
  5. Mayuncommon
  6. Junrare
  7. Juluncommon
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%2%4%6%Jan 1-7: 2.9% of 7987 checklistsJan 8-14: 2.4% of 5561 checklistsJan 15-21: 2.7% of 5613 checklistsJan 22-31: 2.4% of 7881 checklistsFeb 1-7: 2.3% of 5018 checklistsFeb 8-14: 2.1% of 5598 checklistsFeb 15-21: 1.7% of 7247 checklistsFeb 22-28: 1.6% of 5531 checklistsMar 1-7: 1.3% of 6110 checklistsMar 8-14: 1.1% of 6623 checklistsMar 15-21: 0.9% of 7687 checklistsMar 22-31: 0.9% of 11095 checklistsApr 1-7: 1.0% of 7774 checklistsApr 8-14: 1.0% of 8785 checklistsApr 15-21: 1.0% of 9684 checklistsApr 22-30: 1.3% of 13805 checklistsMay 1-7: 0.8% of 11847 checklistsMay 8-14: 0.7% of 13547 checklistsMay 15-21: 0.6% of 13019 checklistsMay 22-31: 0.4% of 20456 checklistsJun 1-7: 0.3% of 12993 checklistsJun 8-14: 0.3% of 11594 checklistsJun 15-21: 0.3% of 11159 checklistsJun 22-30: 0.4% of 13786 checklistsJul 1-7: 0.4% of 9584 checklistsJul 8-14: 0.4% of 9078 checklistsJul 15-21: 0.6% of 7905 checklistsJul 22-31: 0.7% of 10906 checklistsAug 1-7: 0.7% of 7335 checklistsAug 8-14: 0.7% of 6868 checklistsAug 15-21: 1.0% of 6866 checklistsAug 22-31: 1.7% of 10076 checklistsSep 1-7: 2.9% of 7670 checklistsSep 8-14: 3.7% of 7490 checklistsSep 15-21: 4.2% of 6804 checklistsSep 22-30: 3.9% of 8016 checklistsOct 1-7: 3.9% of 5996 checklistsOct 8-14: 3.2% of 6156 checklistsOct 15-21: 2.7% of 5742 checklistsOct 22-31: 2.7% of 7790 checklistsNov 1-7: 2.0% of 5353 checklistsNov 8-14: 2.5% of 5475 checklistsNov 15-21: 2.3% of 4603 checklistsNov 22-30: 2.0% of 6067 checklistsDec 1-7: 1.9% of 4362 checklistsDec 8-14: 2.8% of 4467 checklistsDec 15-21: 3.3% of 5328 checklistsDec 22-31: 2.2% of 6672 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 Montana 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 Montana

Best counties

Share of checklists at the peak
  1. Sheridan CountyBest mid September · 34 checklists that week, 2,316 in all22%
  2. Musselshell CountyBest early October · 17 checklists that week, 961 in all21%
  3. Liberty CountyBest late September · 40 checklists that week, 800 in all13%
  4. Phillips CountyBest early October · 27 checklists that week, 4,818 in all13%
  5. Broadwater CountyBest the second week of December · 13 checklists that week, 2,470 in all13%
  6. Glacier CountyBest mid February · 62 checklists that week, 9,238 in all11%

Best spots

Share of checklists at the peak
  1. Picnic LakesFlathead County, best late September · 24 checklists that week, 135 in all33%
  2. Flathead Lake/Wayfarers State ParkFlathead County, best late April · 25 checklists that week, 635 in all31%
  3. Thompson Falls ReservoirSanders County, best late April · 24 checklists that week, 414 in all26%
  4. Nature ParkLewis and Clark County, best early October · 21 checklists that week, 1,111 in all21%
  5. Boxelder LakeSheridan County, best the second week of September · 26 checklists that week, 209 in all21%

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

Best time of day

In Montana, the Merlin is most often listed on checklists started between 4 and 6 pm (1.7% of those checklists).

0%0.5%1%1.5%2%12 am: too few checklists (183) to judge1 am: too few checklists (169) to judge2 am: too few checklists (163) to judge3 am: too few checklists (212) to judge4 am: too few checklists (503) to judge5 am: too few checklists (4022) to judge6 am: 0.8% of 12719 checklists7 am: 1.4% of 31202 checklists8 am: 1.7% of 47646 checklists9 am: 1.6% of 44624 checklists10 am: 1.5% of 40704 checklists11 am: 1.6% of 33825 checklists12 pm: 1.2% of 29407 checklists1 pm: 1.4% of 27959 checklists2 pm: 1.7% of 26928 checklists3 pm: 1.6% of 25313 checklists4 pm: 1.7% of 22151 checklists5 pm: 1.6% of 16884 checklists6 pm: 1.3% of 13780 checklists7 pm: 0.9% of 9926 checklists8 pm: too few checklists (5765) to judge9 pm: too few checklists (2099) to judge10 pm: too few checklists (595) to judge11 pm: too few checklists (230) 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
January2.9%2.4%2.7%2.4%
February2.3%2.1%1.7%1.6%
March1.3%1.1%0.9%0.9%
April1.0%1.0%1.0%1.3%
May0.8%0.7%0.6%0.4%
June0.3%0.3%0.3%0.4%
July0.4%0.4%0.6%0.7%
August0.7%0.7%1.0%1.7%
September2.9%3.7%4.2%3.9%
October3.9%3.2%2.7%2.7%
November2.0%2.5%2.3%2.0%
December1.9%2.8%3.3%2.2%

Neighboring states

  • Idaho: arrives the second week of September, 3 weeks later than Montana
  • Wyoming: arrives early September, 2 weeks later than Montana
  • Utah: arrives the second week of October, 7 weeks later than Montana
  • Washington: arrives mid July, 4 weeks earlier than Montana

Common questions

When do Merlins arrive in Montana?
Merlins arrive in Montana in mid August, peak in late September (4.0% of checklists), and most are gone by early March.
When do Merlins leave Montana?
Most Merlins have left Montana by early March, when reports fall below half their usual rate. Stragglers are still reported until the second week of March.
When is the best time to see a Merlin in Montana?
The Merlin is reported most often in late September, on about 4.0% of Montana checklists.
Where in Montana are Merlins seen most often?
By county, Sheridan County, Musselshell County, and Liberty County have the highest peak reporting rates for the Merlin (counties with at least 200 checklists).