WhenToBird

Buteo lagopus · Accipitridae

When Do Rough-legged Hawks Arrive in Montana?

Adult Rough-legged Hawk
Photo: Rev. Lee A. Payne, Jr., CC BY 4.0 via iNaturalist

Rough-legged Hawks are winter birds in Montana: the first arrive in early October, they are common by late October, peak in the second week of January (14% of checklists), and most are gone by mid March.

When to look

First arrivalsOct 1-7early October
Common byOct 22-31late October
PeakJan 8-14the second week of January
Most gone byMar 15-21mid March

Best: the second week of January. First arrivals early October; most are gone by mid March. Peak: on about 14% of Montana checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Apruncommon
  5. Maynot usually seen
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octuncommon
  11. Novcommon
  12. Decpeak season

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

0%5%10%15%Jan 1-7: 14% of 7987 checklistsJan 8-14: 15% of 5561 checklistsJan 15-21: 14% of 5613 checklistsJan 22-31: 12% of 7881 checklistsFeb 1-7: 10% of 5018 checklistsFeb 8-14: 12% of 5598 checklistsFeb 15-21: 10% of 7247 checklistsFeb 22-28: 9.7% of 5531 checklistsMar 1-7: 8.0% of 6110 checklistsMar 8-14: 7.5% of 6623 checklistsMar 15-21: 5.7% of 7687 checklistsMar 22-31: 3.6% of 11095 checklistsApr 1-7: 2.2% of 7774 checklistsApr 8-14: 1.8% of 8785 checklistsApr 15-21: 1.0% of 9684 checklistsApr 22-30: 0.4% of 13805 checklistsMay 1-7: 0.1% of 11847 checklistsMay 8-14: 0.1% of 13547 checklistsMay 15-21: 0% of 13019 checklistsMay 22-31: 0% of 20456 checklistsJun 1-7: 0% of 12993 checklistsJun 8-14: 0% of 11594 checklistsJun 15-21: 0% of 11159 checklistsJun 22-30: 0% of 13786 checklistsJul 1-7: 0% of 9584 checklistsJul 8-14: 0% of 9078 checklistsJul 15-21: 0% of 7905 checklistsJul 22-31: 0% of 10906 checklistsAug 1-7: 0% of 7335 checklistsAug 8-14: 0% of 6868 checklistsAug 15-21: 0% of 6866 checklistsAug 22-31: 0% of 10076 checklistsSep 1-7: 0% of 7670 checklistsSep 8-14: 0.1% of 7490 checklistsSep 15-21: 0.1% of 6804 checklistsSep 22-30: 0.2% of 8016 checklistsOct 1-7: 0.9% of 5996 checklistsOct 8-14: 2.2% of 6156 checklistsOct 15-21: 3.2% of 5742 checklistsOct 22-31: 5.3% of 7790 checklistsNov 1-7: 6.9% of 5353 checklistsNov 8-14: 8.4% of 5475 checklistsNov 15-21: 7.6% of 4603 checklistsNov 22-30: 9.2% of 6067 checklistsDec 1-7: 10% of 4362 checklistsDec 8-14: 10% of 4467 checklistsDec 15-21: 13% of 5328 checklistsDec 22-31: 11% 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. Wheatland CountyBest late December · 11 checklists that week, 1,384 in all58%
  2. Deer Lodge CountyBest mid February · 82 checklists that week, 8,732 in all41%
  3. Meagher CountyBest early March · 21 checklists that week, 1,201 in all40%
  4. Broadwater CountyBest mid December · 26 checklists that week, 2,470 in all39%
  5. Powell CountyBest the second week of February · 61 checklists that week, 5,305 in all34%
  6. Big Horn CountyBest late February · 15 checklists that week, 1,279 in all34%

Best spots

Share of checklists at the peak
  1. Old Maids CouleeGlacier County, best late October · 24 checklists that week, 115 in all69%

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

Best time of day

In Montana, the Rough-legged Hawk is most often listed on checklists started between 1 and 3 pm (5.2% of those checklists).

0%2%4%6%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: 0.2% of 12719 checklists7 am: 0.8% of 31202 checklists8 am: 2.6% of 47646 checklists9 am: 4.0% of 44624 checklists10 am: 4.4% of 40704 checklists11 am: 4.8% of 33825 checklists12 pm: 5.1% of 29407 checklists1 pm: 5.1% of 27959 checklists2 pm: 5.3% of 26928 checklists3 pm: 4.6% of 25313 checklists4 pm: 3.3% of 22151 checklists5 pm: 1.3% of 16884 checklists6 pm: 0.6% of 13780 checklists7 pm: 0.3% 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
January14%15%14%12%
February10%12%10%9.7%
March8.0%7.5%5.7%3.6%
April2.2%1.8%1.0%0.4%
May0.1%0.1%0%0%
June0%0%0%0%
July0%0%0%0%
August0%0%0%0%
September0%0.1%0.1%0.2%
October0.9%2.2%3.2%5.3%
November6.9%8.4%7.6%9.2%
December10%10%13%11%

Neighboring states

  • Idaho: arrives late October, 3 weeks later than Montana
  • Wyoming: arrives mid October, 2 weeks later than Montana
  • Utah: arrives the second week of November, 5 weeks later than Montana
  • Washington: arrives late October, 3 weeks later than Montana

Common questions

When do Rough-legged Hawks arrive in Montana?
Rough-legged Hawks are winter birds in Montana: the first arrive in early October, they are common by late October, peak in the second week of January (14% of checklists), and most are gone by mid March.
When do Rough-legged Hawks leave Montana?
Most Rough-legged Hawks have left Montana by mid March, when reports fall below half their usual rate. Stragglers are still reported until the second week of April.
When is the best time to see a Rough-legged Hawk in Montana?
The Rough-legged Hawk is reported most often in the second week of January, on about 14% of Montana checklists.
Where in Montana are Rough-legged Hawks seen most often?
By county, Wheatland County, Deer Lodge County, and Meagher County have the highest peak reporting rates for the Rough-legged Hawk (counties with at least 200 checklists).