WhenToBird

Circus hudsonius · Accipitridae

When Do Northern Harriers Arrive in Arizona?

Northern Harriers are winter birds in Arizona: the first arrive in late August, they are common by early October, peak in late November (9.6% of checklists), and most are gone by the second week of March.

When to look

First arrivalsAug 22-31late August
Common byOct 1-7early October
PeakNov 22-30late November
Most gone byMar 8-14the second week of March

Best: late November. First arrivals late August; most are gone by the second week of March. Peak: on about 9.6% of Arizona checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Apruncommon
  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%5%10%15%Jan 1-7: 8.9% of 34758 checklistsJan 8-14: 10% of 29835 checklistsJan 15-21: 9.2% of 29279 checklistsJan 22-31: 8.5% of 39716 checklistsFeb 1-7: 7.9% of 27299 checklistsFeb 8-14: 7.0% of 28703 checklistsFeb 15-21: 5.7% of 35357 checklistsFeb 22-28: 5.6% of 29889 checklistsMar 1-7: 5.1% of 29932 checklistsMar 8-14: 4.6% of 32982 checklistsMar 15-21: 4.1% of 34731 checklistsMar 22-31: 2.9% of 50213 checklistsApr 1-7: 2.3% of 35788 checklistsApr 8-14: 1.6% of 38087 checklistsApr 15-21: 1.2% of 41520 checklistsApr 22-30: 0.7% of 55218 checklistsMay 1-7: 0.4% of 39688 checklistsMay 8-14: 0.2% of 39398 checklistsMay 15-21: 0.1% of 29562 checklistsMay 22-31: 0.1% of 36774 checklistsJun 1-7: 0.1% of 21313 checklistsJun 8-14: 0.1% of 19129 checklistsJun 15-21: 0.1% of 17922 checklistsJun 22-30: 0.1% of 21188 checklistsJul 1-7: 0.1% of 17325 checklistsJul 8-14: 0.1% of 16463 checklistsJul 15-21: 0.1% of 18642 checklistsJul 22-31: 0.2% of 31215 checklistsAug 1-7: 0.4% of 28163 checklistsAug 8-14: 0.6% of 31329 checklistsAug 15-21: 0.7% of 23878 checklistsAug 22-31: 1.1% of 28508 checklistsSep 1-7: 1.8% of 20878 checklistsSep 8-14: 2.1% of 19671 checklistsSep 15-21: 2.6% of 19859 checklistsSep 22-30: 3.5% of 25179 checklistsOct 1-7: 4.2% of 19420 checklistsOct 8-14: 4.8% of 21925 checklistsOct 15-21: 5.8% of 20995 checklistsOct 22-31: 7.0% of 29258 checklistsNov 1-7: 8.0% of 21269 checklistsNov 8-14: 8.5% of 22753 checklistsNov 15-21: 9.4% of 21982 checklistsNov 22-30: 9.5% of 29475 checklistsDec 1-7: 9.9% of 20810 checklistsDec 8-14: 8.6% of 22229 checklistsDec 15-21: 8.3% of 25148 checklistsDec 22-31: 8.6% of 39567 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 Arizona 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 Arizona

Best counties

Share of checklists at the peak
  1. Cochise CountyBest mid January · 3064 checklists that week, 190,093 in all21%
  2. La Paz CountyBest early December · 162 checklists that week, 7,279 in all21%
  3. Yuma CountyBest mid November · 216 checklists that week, 14,687 in all19%
  4. Pinal CountyBest the second week of December · 724 checklists that week, 40,036 in all15%
  5. Greenlee CountyBest the second week of December · 10 checklists that week, 2,745 in all15%
  6. Graham CountyBest early February · 147 checklists that week, 9,876 in all14%

Best spots

Share of checklists at the peak
  1. Whitewater Draw Wildlife AreaCochise County, best the second week of October · 78 checklists that week, 5,324 in all87%
  2. Environmental Operations ParkCochise County, best the second week of December · 22 checklists that week, 1,829 in all83%
  3. Coronado National Forest (Meadow Valley)Santa Cruz County, best mid February · 29 checklists that week, 496 in all79%
  4. Arlington Wildlife AreaMaricopa County, best mid November · 36 checklists that week, 760 in all76%

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

Best time of day

In Arizona, the Northern Harrier is most often listed on checklists started between 8 and 10 am (5.0% of those checklists).

0%2%4%6%12 am: too few checklists (488) to judge1 am: too few checklists (503) to judge2 am: too few checklists (489) to judge3 am: too few checklists (735) to judge4 am: too few checklists (4115) to judge5 am: 0.7% of 38350 checklists6 am: 2.6% of 118786 checklists7 am: 4.6% of 183415 checklists8 am: 5.0% of 187346 checklists9 am: 5.0% of 151342 checklists10 am: 4.6% of 124522 checklists11 am: 4.1% of 97088 checklists12 pm: 4.1% of 78110 checklists1 pm: 4.4% of 73059 checklists2 pm: 4.6% of 68912 checklists3 pm: 4.6% of 68060 checklists4 pm: 3.4% of 69387 checklists5 pm: 1.8% of 52951 checklists6 pm: 0.5% of 31061 checklists7 pm: too few checklists (16076) to judge8 pm: too few checklists (5352) to judge9 pm: too few checklists (2369) to judge10 pm: too few checklists (1100) to judge11 pm: too few checklists (604) 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
January8.9%10%9.2%8.5%
February7.9%7.0%5.7%5.6%
March5.1%4.6%4.1%2.9%
April2.3%1.6%1.2%0.7%
May0.4%0.2%0.1%0.1%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.2%
August0.4%0.6%0.7%1.1%
September1.8%2.1%2.6%3.5%
October4.2%4.8%5.8%7.0%
November8.0%8.5%9.4%9.5%
December9.9%8.6%8.3%8.6%

Neighboring states

  • New Mexico: arrives late August, in the same week than Arizona
  • Nevada: arrives the second week of October, 6 weeks later than Arizona
  • Utah: arrives the second week of August, 2 weeks earlier than Arizona
  • California: arrives the second week of October, 6 weeks later than Arizona

Common questions

When do Northern Harriers arrive in Arizona?
Northern Harriers are winter birds in Arizona: the first arrive in late August, they are common by early October, peak in late November (9.6% of checklists), and most are gone by the second week of March.
When do Northern Harriers leave Arizona?
Most Northern Harriers have left Arizona by the second week of March, 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 Arizona?
The Northern Harrier is reported most often in late November, on about 9.6% of Arizona checklists.
Where in Arizona are Northern Harriers seen most often?
By county, Cochise County, La Paz County, and Yuma County have the highest peak reporting rates for the Northern Harrier (counties with at least 200 checklists).