WhenToBird

Ardea herodias · Ardeidae

When Do Great Blue Herons Arrive in New Hampshire?

Adult Great Blue Heron
Photo: mostbittern, CC BY 4.0 via iNaturalist

Great Blue Herons reach New Hampshire in the second week of March, are common by late March, peak in late August (19% of checklists), and most are gone by the second week of November.

When to look

First arrivalsMar 8-14the second week of March
Common byMar 22-31late March
PeakAug 22-31late August
Most gone byNov 8-14the second week of November

Best: late August. First arrivals the second week of March; most are gone by the second week of November. Peak: on about 19% of New Hampshire checklists.

  1. Janrare
  2. Febnot usually seen
  3. Maruncommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decuncommon

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

0%5%10%15%20%Jan 1-7: 1.3% of 8253 checklistsJan 8-14: 0.9% of 5998 checklistsJan 15-21: 0.8% of 5734 checklistsJan 22-31: 0.6% of 7776 checklistsFeb 1-7: 0.5% of 5253 checklistsFeb 8-14: 0.5% of 6802 checklistsFeb 15-21: 0.4% of 8852 checklistsFeb 22-28: 0.6% of 5792 checklistsMar 1-7: 0.8% of 6187 checklistsMar 8-14: 1.2% of 6977 checklistsMar 15-21: 3.3% of 7863 checklistsMar 22-31: 6.8% of 11746 checklistsApr 1-7: 10% of 9329 checklistsApr 8-14: 11% of 10499 checklistsApr 15-21: 11% of 10376 checklistsApr 22-30: 13% of 13086 checklistsMay 1-7: 12% of 13198 checklistsMay 8-14: 11% of 14980 checklistsMay 15-21: 11% of 12487 checklistsMay 22-31: 11% of 14294 checklistsJun 1-7: 10% of 8974 checklistsJun 8-14: 11% of 8395 checklistsJun 15-21: 10% of 7670 checklistsJun 22-30: 11% of 9188 checklistsJul 1-7: 11% of 7707 checklistsJul 8-14: 14% of 6554 checklistsJul 15-21: 15% of 6636 checklistsJul 22-31: 17% of 9599 checklistsAug 1-7: 18% of 6436 checklistsAug 8-14: 19% of 6477 checklistsAug 15-21: 19% of 6510 checklistsAug 22-31: 19% of 9762 checklistsSep 1-7: 19% of 6700 checklistsSep 8-14: 19% of 6012 checklistsSep 15-21: 18% of 6238 checklistsSep 22-30: 16% of 7619 checklistsOct 1-7: 15% of 6702 checklistsOct 8-14: 13% of 6863 checklistsOct 15-21: 11% of 6284 checklistsOct 22-31: 9.8% of 8287 checklistsNov 1-7: 9.0% of 7584 checklistsNov 8-14: 6.7% of 6056 checklistsNov 15-21: 4.9% of 5597 checklistsNov 22-30: 4.5% of 7140 checklistsDec 1-7: 2.6% of 4623 checklistsDec 8-14: 2.1% of 4920 checklistsDec 15-21: 1.6% of 6416 checklistsDec 22-31: 1.3% of 7659 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 Hampshire 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 Hampshire

Best counties

Share of checklists at the peak
  1. Strafford CountyBest early September · 572 checklists that week, 41,888 in all35%
  2. Rockingham CountyBest early September · 1456 checklists that week, 84,864 in all27%
  3. Merrimack CountyBest late August · 898 checklists that week, 36,980 in all20%
  4. Hillsborough CountyBest the second week of August · 666 checklists that week, 50,125 in all20%
  5. Coos CountyBest late August · 692 checklists that week, 27,719 in all17%
  6. Cheshire CountyBest early September · 639 checklists that week, 39,834 in all16%

Best spots

Share of checklists at the peak
  1. Copps PondCarroll County, best the second week of August · 23 checklists that week, 473 in all95%
  2. Horseshoe PondMerrimack County, best mid August · 29 checklists that week, 2,088 in all91%
  3. Horseshoe Pond (Thorntons Ferry)Hillsborough County, best the second week of August · 25 checklists that week, 1,018 in all87%
  4. Elm Brook Recreation AreaMerrimack County, best late July · 28 checklists that week, 1,090 in all85%

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

Best time of day

In New Hampshire, the Great Blue Heron is most often listed on checklists started between 6 and 8 am (13% of those checklists).

0%5%10%15%20%12 am: too few checklists (219) to judge1 am: too few checklists (192) to judge2 am: too few checklists (176) to judge3 am: too few checklists (234) to judge4 am: too few checklists (1042) to judge5 am: too few checklists (6352) to judge6 am: 15% of 23140 checklists7 am: 11% of 43401 checklists8 am: 11% of 48039 checklists9 am: 8.9% of 43328 checklists10 am: 8.5% of 37073 checklists11 am: 7.7% of 32028 checklists12 pm: 7.2% of 27396 checklists1 pm: 7.4% of 25182 checklists2 pm: 7.2% of 24318 checklists3 pm: 8.0% of 21974 checklists4 pm: 9.9% of 17958 checklists5 pm: 11% of 14528 checklists6 pm: 12% of 9144 checklists7 pm: too few checklists (5341) to judge8 pm: too few checklists (1845) to judge9 pm: too few checklists (578) to judge10 pm: too few checklists (346) to judge11 pm: too few checklists (256) 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
January1.3%0.9%0.8%0.6%
February0.5%0.5%0.4%0.6%
March0.8%1.2%3.3%6.8%
April10%11%11%13%
May12%11%11%11%
June10%11%10%11%
July11%14%15%17%
August18%19%19%19%
September19%19%18%16%
October15%13%11%9.8%
November9.0%6.7%4.9%4.5%
December2.6%2.1%1.6%1.3%

Neighboring states

  • Massachusetts: arrives the second week of April, 4 weeks later than New Hampshire
  • Vermont: arrives mid March, 1 week later than New Hampshire
  • Rhode Island: arrives early July, 15 weeks later than New Hampshire
  • Maine: arrives mid March, 1 week later than New Hampshire

Common questions

When do Great Blue Herons arrive in New Hampshire?
Great Blue Herons reach New Hampshire in the second week of March, are common by late March, peak in late August (19% of checklists), and most are gone by the second week of November.
When do Great Blue Herons leave New Hampshire?
Most Great Blue Herons have left New Hampshire by the second week of November, when reports fall below half their usual rate. Stragglers are still reported until early January.
When is the best time to see a Great Blue Heron in New Hampshire?
The Great Blue Heron is reported most often in late August, on about 19% of New Hampshire checklists.
Where in New Hampshire are Great Blue Herons seen most often?
By county, Strafford County, Rockingham County, and Merrimack County have the highest peak reporting rates for the Great Blue Heron (counties with at least 200 checklists).