WhenToBird

Astur cooperii · Accipitridae

When Do Cooper's Hawks Arrive in Montana?

Adult male Cooper's Hawk
Photo: Shirley Zundell, CC BY 4.0 via iNaturalist

Cooper's Hawks arrive in Montana in early April, peak in the second week of September (3.8% of checklists), and most are gone by late October.

When to look

First arrivalsApr 1-7early April
Common byApr 1-7early April
PeakSep 8-14the second week of September
Most gone byOct 22-31late October

Best: the second week of September. First arrivals early April; most are gone by late October. Peak: on about 3.8% of Montana checklists.

  1. Januncommon
  2. Febuncommon
  3. Maruncommon
  4. Aprcommon
  5. Maycommon
  6. Jununcommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octcommon
  11. Novuncommon
  12. Decuncommon

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

0%2%4%6%Jan 1-7: 0.6% of 7987 checklistsJan 8-14: 0.6% of 5561 checklistsJan 15-21: 0.6% of 5613 checklistsJan 22-31: 0.8% of 7881 checklistsFeb 1-7: 0.6% of 5018 checklistsFeb 8-14: 0.5% of 5598 checklistsFeb 15-21: 0.5% of 7247 checklistsFeb 22-28: 0.7% of 5531 checklistsMar 1-7: 0.7% of 6110 checklistsMar 8-14: 0.5% of 6623 checklistsMar 15-21: 0.6% of 7687 checklistsMar 22-31: 0.7% of 11095 checklistsApr 1-7: 1.4% of 7774 checklistsApr 8-14: 1.8% of 8785 checklistsApr 15-21: 2.0% of 9684 checklistsApr 22-30: 2.6% of 13805 checklistsMay 1-7: 2.1% of 11847 checklistsMay 8-14: 1.9% of 13547 checklistsMay 15-21: 2.3% of 13019 checklistsMay 22-31: 1.8% of 20456 checklistsJun 1-7: 1.4% of 12993 checklistsJun 8-14: 1.2% of 11594 checklistsJun 15-21: 1.1% of 11159 checklistsJun 22-30: 1.2% of 13786 checklistsJul 1-7: 1.1% of 9584 checklistsJul 8-14: 1.1% of 9078 checklistsJul 15-21: 1.6% of 7905 checklistsJul 22-31: 1.2% of 10906 checklistsAug 1-7: 1.9% of 7335 checklistsAug 8-14: 1.8% of 6868 checklistsAug 15-21: 2.6% of 6866 checklistsAug 22-31: 3.0% of 10076 checklistsSep 1-7: 3.6% of 7670 checklistsSep 8-14: 4.0% of 7490 checklistsSep 15-21: 3.8% of 6804 checklistsSep 22-30: 3.4% of 8016 checklistsOct 1-7: 2.4% of 5996 checklistsOct 8-14: 1.6% of 6156 checklistsOct 15-21: 1.1% of 5742 checklistsOct 22-31: 0.9% of 7790 checklistsNov 1-7: 0.9% of 5353 checklistsNov 8-14: 0.9% of 5475 checklistsNov 15-21: 0.7% of 4603 checklistsNov 22-30: 0.6% of 6067 checklistsDec 1-7: 0.7% of 4362 checklistsDec 8-14: 0.9% of 4467 checklistsDec 15-21: 0.8% of 5328 checklistsDec 22-31: 0.7% 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. Yellowstone CountyBest early September · 226 checklists that week, 13,895 in all16%
  2. Sheridan CountyBest late September · 13 checklists that week, 2,316 in all11%
  3. Musselshell CountyBest early April · 14 checklists that week, 961 in all10%
  4. Custer CountyBest the second week of August · 13 checklists that week, 1,404 in all9.9%
  5. Rosebud CountyBest early October · 11 checklists that week, 795 in all9.1%
  6. Powder River CountyBest the second week of September · 10 checklists that week, 598 in all8.7%

Best spots

Share of checklists at the peak
  1. Picnic LakesFlathead County, best late September · 24 checklists that week, 135 in all83%
  2. East Gallatin Recreation Area (Bridger Creek)Gallatin County, best early May · 30 checklists that week, 988 in all26%
  3. Cemetery ParkGallatin County, best mid April · 22 checklists that week, 1,029 in all25%
  4. Glacier National Park (Snyder Creek)Flathead County, best the second week of October · 25 checklists that week, 333 in all24%
  5. Greenough ParkMissoula County, best mid August · 42 checklists that week, 2,749 in all19%

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

Best time of day

In Montana, the Cooper's Hawk is most often listed on checklists started between 6 and 8 am (2.3% of those checklists).

0%1%2%3%4%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: 3.1% of 12719 checklists7 am: 2.0% of 31202 checklists8 am: 1.6% of 47646 checklists9 am: 1.6% of 44624 checklists10 am: 1.7% of 40704 checklists11 am: 1.7% of 33825 checklists12 pm: 1.3% of 29407 checklists1 pm: 1.3% of 27959 checklists2 pm: 1.2% of 26928 checklists3 pm: 1.1% of 25313 checklists4 pm: 1.5% of 22151 checklists5 pm: 1.3% of 16884 checklists6 pm: 1.6% of 13780 checklists7 pm: 1.3% 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
January0.6%0.6%0.6%0.8%
February0.6%0.5%0.5%0.7%
March0.7%0.5%0.6%0.7%
April1.4%1.8%2.0%2.6%
May2.1%1.9%2.3%1.8%
June1.4%1.2%1.1%1.2%
July1.1%1.1%1.6%1.2%
August1.9%1.8%2.6%3.0%
September3.6%4.0%3.8%3.4%
October2.4%1.6%1.1%0.9%
November0.9%0.9%0.7%0.6%
December0.7%0.9%0.8%0.7%

Neighboring states

  • Idaho: arrives early September, 20 weeks later than Montana
  • Wyoming: arrives the second week of July, 13 weeks later than Montana
  • Utah: year-round, peaks mid September
  • Washington: year-round, peaks early October

Common questions

When do Cooper's Hawks arrive in Montana?
Cooper's Hawks arrive in Montana in early April, peak in the second week of September (3.8% of checklists), and most are gone by late October.
When do Cooper's Hawks leave Montana?
Most Cooper's Hawks have left Montana by late October, when reports fall below half their usual rate.
When is the best time to see a Cooper's Hawk in Montana?
The Cooper's Hawk is reported most often in the second week of September, on about 3.8% of Montana checklists.
Where in Montana are Cooper's Hawks seen most often?
By county, Yellowstone County, Sheridan County, and Musselshell County have the highest peak reporting rates for the Cooper's Hawk (counties with at least 200 checklists).