WhenToBird

Circus hudsonius · Accipitridae

When Do Northern Harriers Arrive in Missouri?

Northern Harriers are winter birds in Missouri: the first arrive in late September, they are common by the second week of October, peak in the second week of December (7.6% of checklists), and most are gone by early April.

When to look

First arrivalsSep 22-30late September
Common byOct 8-14the second week of October
PeakDec 8-14the second week of December
Most gone byApr 1-7early April

Best: the second week of December. First arrivals late September; most are gone by early April. Peak: on about 7.6% of Missouri checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augrare
  9. Sepuncommon
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

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

0%2%4%6%8%Jan 1-7: 6.6% of 12628 checklistsJan 8-14: 5.8% of 9076 checklistsJan 15-21: 6.4% of 8790 checklistsJan 22-31: 6.2% of 11986 checklistsFeb 1-7: 5.5% of 8987 checklistsFeb 8-14: 4.0% of 10394 checklistsFeb 15-21: 3.3% of 15472 checklistsFeb 22-28: 4.4% of 9917 checklistsMar 1-7: 3.9% of 9877 checklistsMar 8-14: 3.6% of 9570 checklistsMar 15-21: 4.0% of 10274 checklistsMar 22-31: 3.8% of 16156 checklistsApr 1-7: 3.4% of 12774 checklistsApr 8-14: 1.9% of 14048 checklistsApr 15-21: 1.7% of 14894 checklistsApr 22-30: 0.9% of 23288 checklistsMay 1-7: 0.4% of 22645 checklistsMay 8-14: 0.1% of 21384 checklistsMay 15-21: 0.1% of 13989 checklistsMay 22-31: 0.1% of 15784 checklistsJun 1-7: 0.1% of 9691 checklistsJun 8-14: 0.1% of 9036 checklistsJun 15-21: 0.1% of 7907 checklistsJun 22-30: 0.1% of 9831 checklistsJul 1-7: 0.1% of 8008 checklistsJul 8-14: 0.1% of 7202 checklistsJul 15-21: 0.1% of 7151 checklistsJul 22-31: 0.1% of 9833 checklistsAug 1-7: 0.2% of 7639 checklistsAug 8-14: 0.2% of 7507 checklistsAug 15-21: 0.3% of 7429 checklistsAug 22-31: 0.5% of 11182 checklistsSep 1-7: 0.6% of 9471 checklistsSep 8-14: 0.6% of 8501 checklistsSep 15-21: 0.7% of 8169 checklistsSep 22-30: 1.5% of 11572 checklistsOct 1-7: 2.2% of 9028 checklistsOct 8-14: 3.1% of 9413 checklistsOct 15-21: 3.8% of 8656 checklistsOct 22-31: 4.9% of 11625 checklistsNov 1-7: 5.7% of 8627 checklistsNov 8-14: 5.6% of 8284 checklistsNov 15-21: 6.9% of 8075 checklistsNov 22-30: 6.9% of 10430 checklistsDec 1-7: 7.8% of 7870 checklistsDec 8-14: 7.1% of 7567 checklistsDec 15-21: 7.8% of 9696 checklistsDec 22-31: 6.1% of 13142 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 Missouri 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 Missouri

Best counties

Share of checklists at the peak
  1. Barton CountyBest early December · 32 checklists that week, 1,629 in all65%
  2. Pike CountyBest late November · 38 checklists that week, 1,685 in all59%
  3. St. Clair CountyBest the second week of November · 28 checklists that week, 1,484 in all58%
  4. Pemiscot CountyBest the second week of December · 27 checklists that week, 1,602 in all45%
  5. Vernon CountyBest mid November · 15 checklists that week, 1,443 in all45%
  6. Dade CountyBest the second week of January · 96 checklists that week, 3,618 in all41%

Best spots

Share of checklists at the peak
  1. Prairie State ParkBarton County, best late November · 24 checklists that week, 351 in all90%
  2. Clarence Cannon National Wildlife RefugePike County, best late November · 26 checklists that week, 708 in all88%
  3. Hi Lonesome Prairie Conservation AreaBenton County, best late November · 33 checklists that week, 578 in all83%
  4. Taberville Prairie Natural AreaSt. Clair County, best late March · 21 checklists that week, 269 in all79%
  5. Leach (B.K.) Memorial Conservation AreaLincoln County, best early January · 21 checklists that week, 572 in all69%

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

Best time of day

In Missouri, the Northern Harrier is most often listed on checklists started between 1 and 3 pm (4.0% of those checklists).

0%2%4%6%12 am: too few checklists (205) to judge1 am: too few checklists (179) to judge2 am: too few checklists (204) to judge3 am: too few checklists (216) to judge4 am: too few checklists (630) to judge5 am: too few checklists (5072) to judge6 am: 1.8% of 27231 checklists7 am: 1.9% of 64162 checklists8 am: 2.2% of 67854 checklists9 am: 3.0% of 56515 checklists10 am: 3.2% of 47496 checklists11 am: 3.2% of 38845 checklists12 pm: 3.3% of 33383 checklists1 pm: 3.9% of 32503 checklists2 pm: 4.1% of 32615 checklists3 pm: 3.6% of 32514 checklists4 pm: 3.8% of 30274 checklists5 pm: 2.0% of 23446 checklists6 pm: 0.9% of 16374 checklists7 pm: too few checklists (10236) to judge8 pm: too few checklists (3133) to judge9 pm: too few checklists (722) to judge10 pm: too few checklists (405) to judge11 pm: too few checklists (261) 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
January6.6%5.8%6.4%6.2%
February5.5%4.0%3.3%4.4%
March3.9%3.6%4.0%3.8%
April3.4%1.9%1.7%0.9%
May0.4%0.1%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0.2%0.2%0.3%0.5%
September0.6%0.6%0.7%1.5%
October2.2%3.1%3.8%4.9%
November5.7%5.6%6.9%6.9%
December7.8%7.1%7.8%6.1%

Neighboring states

  • Arkansas: arrives late September, in the same week than Missouri
  • Iowa: arrives early September, 3 weeks earlier than Missouri
  • Kansas: arrives late August, 4 weeks earlier than Missouri
  • Illinois: arrives mid September, 1 week earlier than Missouri

Common questions

When do Northern Harriers arrive in Missouri?
Northern Harriers are winter birds in Missouri: the first arrive in late September, they are common by the second week of October, peak in the second week of December (7.6% of checklists), and most are gone by early April.
When do Northern Harriers leave Missouri?
Most Northern Harriers have left Missouri by early April, when reports fall below half their usual rate. Stragglers are still reported until mid April.
When is the best time to see a Northern Harrier in Missouri?
The Northern Harrier is reported most often in the second week of December, on about 7.6% of Missouri checklists.
Where in Missouri are Northern Harriers seen most often?
By county, Barton County, Pike County, and St. Clair County have the highest peak reporting rates for the Northern Harrier (counties with at least 200 checklists).