WhenToBird

Circus hudsonius · Accipitridae

When Do Northern Harriers Arrive in New Jersey?

Northern Harriers are winter birds in New Jersey: the first arrive in late August, they are common by the second week of September, peak in mid October (13% of checklists), and most are gone by the second week of April.

When to look

First arrivalsAug 22-31late August
Common bySep 8-14the second week of September
PeakOct 15-21mid October
Most gone byApr 8-14the second week of April

Best: mid October. First arrivals late August; most are gone by the second week of April. Peak: on about 13% of New Jersey checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augrare
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%5%10%15%Jan 1-7: 7.3% of 28167 checklistsJan 8-14: 7.9% of 20583 checklistsJan 15-21: 8.5% of 19739 checklistsJan 22-31: 8.6% of 24586 checklistsFeb 1-7: 8.4% of 17226 checklistsFeb 8-14: 7.4% of 19567 checklistsFeb 15-21: 5.9% of 26553 checklistsFeb 22-28: 6.8% of 19046 checklistsMar 1-7: 6.2% of 17969 checklistsMar 8-14: 5.4% of 18976 checklistsMar 15-21: 5.8% of 18581 checklistsMar 22-31: 5.0% of 27590 checklistsApr 1-7: 4.7% of 21202 checklistsApr 8-14: 4.3% of 23609 checklistsApr 15-21: 3.1% of 25056 checklistsApr 22-30: 1.8% of 36679 checklistsMay 1-7: 1.3% of 38378 checklistsMay 8-14: 0.9% of 44071 checklistsMay 15-21: 0.5% of 34076 checklistsMay 22-31: 0.3% of 32558 checklistsJun 1-7: 0.1% of 18049 checklistsJun 8-14: 0.2% of 15597 checklistsJun 15-21: 0.1% of 14894 checklistsJun 22-30: 0.1% of 17187 checklistsJul 1-7: 0.1% of 13406 checklistsJul 8-14: 0.1% of 12550 checklistsJul 15-21: 0.1% of 12358 checklistsJul 22-31: 0.1% of 18382 checklistsAug 1-7: 0.2% of 13689 checklistsAug 8-14: 0.3% of 14006 checklistsAug 15-21: 0.7% of 14483 checklistsAug 22-31: 1.5% of 23182 checklistsSep 1-7: 2.6% of 17984 checklistsSep 8-14: 3.8% of 18320 checklistsSep 15-21: 7.2% of 20491 checklistsSep 22-30: 9.0% of 26176 checklistsOct 1-7: 9.3% of 24112 checklistsOct 8-14: 12% of 24603 checklistsOct 15-21: 14% of 24549 checklistsOct 22-31: 13% of 26206 checklistsNov 1-7: 11% of 17469 checklistsNov 8-14: 10% of 15102 checklistsNov 15-21: 10% of 14958 checklistsNov 22-30: 8.8% of 19447 checklistsDec 1-7: 7.7% of 14017 checklistsDec 8-14: 7.6% of 14625 checklistsDec 15-21: 7.6% of 16937 checklistsDec 22-31: 8.7% of 26651 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 New Jersey 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 New Jersey

Best counties

Share of checklists at the peak
  1. Atlantic CountyBest mid November · 512 checklists that week, 28,208 in all29%
  2. Cumberland CountyBest late October · 211 checklists that week, 13,927 in all29%
  3. Salem CountyBest mid January · 256 checklists that week, 9,658 in all26%
  4. Cape May CountyBest late October · 7449 checklists that week, 189,832 in all24%
  5. Mercer CountyBest mid December · 1083 checklists that week, 56,614 in all18%
  6. Warren CountyBest mid January · 357 checklists that week, 20,077 in all18%

Best spots

Share of checklists at the peak
  1. Burlington County FairgroundsBurlington County, best late December · 135 checklists that week, 1,739 in all93%
  2. Rosedale ParkMercer County, best late January · 202 checklists that week, 6,841 in all91%
  3. Featherbed Lane Wildlife Management AreaSalem County, best mid January · 33 checklists that week, 563 in all90%
  4. Dennis Creek Wildlife Management AreaCape May County, best late February · 34 checklists that week, 1,924 in all88%
  5. Brigantine National Wilderness Area (Wigwam Creek)Atlantic County, best late January · 39 checklists that week, 398 in all88%
  6. Alpha Grasslands Wildlife Management AreaWarren County, best mid February · 25 checklists that week, 378 in all84%

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

Best time of day

In New Jersey, the Northern Harrier is most often listed on checklists started between 3 and 5 pm (6.4% of those checklists).

0%2%4%6%8%12 am: too few checklists (746) to judge1 am: too few checklists (640) to judge2 am: too few checklists (606) to judge3 am: too few checklists (755) to judge4 am: too few checklists (1681) to judge5 am: too few checklists (11258) to judge6 am: 4.4% of 50447 checklists7 am: 4.9% of 118312 checklists8 am: 4.8% of 123273 checklists9 am: 5.3% of 107783 checklists10 am: 5.8% of 97537 checklists11 am: 5.5% of 82427 checklists12 pm: 5.5% of 72581 checklists1 pm: 5.9% of 71478 checklists2 pm: 6.1% of 69994 checklists3 pm: 6.3% of 66822 checklists4 pm: 6.5% of 55950 checklists5 pm: 3.6% of 41360 checklists6 pm: 2.0% of 28122 checklists7 pm: too few checklists (14727) to judge8 pm: too few checklists (4257) to judge9 pm: too few checklists (1273) to judge10 pm: too few checklists (920) to judge11 pm: too few checklists (693) 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
January7.3%7.9%8.5%8.6%
February8.4%7.4%5.9%6.8%
March6.2%5.4%5.8%5.0%
April4.7%4.3%3.1%1.8%
May1.3%0.9%0.5%0.3%
June0.1%0.2%0.1%0.1%
July0.1%0.1%0.1%0.1%
August0.2%0.3%0.7%1.5%
September2.6%3.8%7.2%9.0%
October9.3%12%14%13%
November11%10%10%8.8%
December7.7%7.6%7.6%8.7%

Neighboring states

  • Delaware: arrives mid August, 1 week earlier than New Jersey
  • Connecticut: arrives mid August, 1 week earlier than New Jersey
  • Pennsylvania: arrives the second week of September, 2 weeks later than New Jersey
  • New York: arrives mid August, 1 week earlier than New Jersey

Common questions

When do Northern Harriers arrive in New Jersey?
Northern Harriers are winter birds in New Jersey: the first arrive in late August, they are common by the second week of September, peak in mid October (13% of checklists), and most are gone by the second week of April.
When do Northern Harriers leave New Jersey?
Most Northern Harriers have left New Jersey by the second week of April, when reports fall below half their usual rate. Stragglers are still reported until early May.
When is the best time to see a Northern Harrier in New Jersey?
The Northern Harrier is reported most often in mid October, on about 13% of New Jersey checklists.
Where in New Jersey are Northern Harriers seen most often?
By county, Atlantic County, Cumberland County, and Salem County have the highest peak reporting rates for the Northern Harrier (counties with at least 200 checklists).