WhenToBird

Ardea herodias · Ardeidae

When Do Great Blue Herons Arrive in Maine?

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

Great Blue Herons reach Maine in mid March, are common by the second week of April, peak in early September (23% of checklists), and most are gone by the second week of November.

When to look

First arrivalsMar 15-21mid March
Common byApr 8-14the second week of April
PeakSep 1-7early September
Most gone byNov 8-14the second week of November

Best: early September. First arrivals mid March; most are gone by the second week of November. Peak: on about 23% of Maine checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Apruncommon
  5. Mayuncommon
  6. Jununcommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decrare

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

0%10%20%30%Jan 1-7: 0.9% of 15499 checklistsJan 8-14: 0.8% of 11141 checklistsJan 15-21: 0.4% of 10729 checklistsJan 22-31: 0.4% of 15084 checklistsFeb 1-7: 0.1% of 9403 checklistsFeb 8-14: 0.3% of 11268 checklistsFeb 15-21: 0.2% of 14061 checklistsFeb 22-28: 0.3% of 9977 checklistsMar 1-7: 0.4% of 9649 checklistsMar 8-14: 0.4% of 11781 checklistsMar 15-21: 0.9% of 11613 checklistsMar 22-31: 2.2% of 17798 checklistsApr 1-7: 6.2% of 14638 checklistsApr 8-14: 8.0% of 16511 checklistsApr 15-21: 7.8% of 17164 checklistsApr 22-30: 7.6% of 22602 checklistsMay 1-7: 7.1% of 22556 checklistsMay 8-14: 6.6% of 27842 checklistsMay 15-21: 7.5% of 27748 checklistsMay 22-31: 6.9% of 38715 checklistsJun 1-7: 6.4% of 26916 checklistsJun 8-14: 6.9% of 23737 checklistsJun 15-21: 7.8% of 22733 checklistsJun 22-30: 7.8% of 28248 checklistsJul 1-7: 9.3% of 20290 checklistsJul 8-14: 12% of 18534 checklistsJul 15-21: 15% of 17319 checklistsJul 22-31: 18% of 22815 checklistsAug 1-7: 20% of 15004 checklistsAug 8-14: 21% of 14603 checklistsAug 15-21: 22% of 14972 checklistsAug 22-31: 23% of 19813 checklistsSep 1-7: 22% of 14567 checklistsSep 8-14: 22% of 14520 checklistsSep 15-21: 22% of 14339 checklistsSep 22-30: 20% of 16879 checklistsOct 1-7: 19% of 12959 checklistsOct 8-14: 18% of 13168 checklistsOct 15-21: 16% of 11184 checklistsOct 22-31: 13% of 13717 checklistsNov 1-7: 11% of 9823 checklistsNov 8-14: 7.4% of 9007 checklistsNov 15-21: 5.8% of 8528 checklistsNov 22-30: 4.1% of 10228 checklistsDec 1-7: 2.3% of 7505 checklistsDec 8-14: 2.1% of 7982 checklistsDec 15-21: 1.6% of 10455 checklistsDec 22-31: 0.9% of 14285 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 Maine 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 Maine

Best counties

Share of checklists at the peak
  1. Knox CountyBest early September · 836 checklists that week, 34,453 in all32%
  2. Waldo CountyBest the second week of September · 592 checklists that week, 33,433 in all30%
  3. York CountyBest the second week of September · 1999 checklists that week, 101,844 in all29%
  4. Aroostook CountyBest mid August · 162 checklists that week, 16,817 in all28%
  5. Cumberland CountyBest early August · 2681 checklists that week, 169,501 in all27%
  6. Sagadahoc CountyBest mid July · 500 checklists that week, 21,736 in all25%

Best spots

Share of checklists at the peak
  1. Wharton PointCumberland County, best late September · 45 checklists that week, 2,229 in all91%
  2. Back CreekYork County, best the second week of October · 36 checklists that week, 620 in all87%
  3. Mill CoveWaldo County, best late August · 28 checklists that week, 399 in all86%
  4. Bass Harbor MarshHancock County, best early September · 21 checklists that week, 513 in all85%
  5. Webhannet River MarshYork County, best mid September · 49 checklists that week, 1,758 in all83%

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

Best time of day

In Maine, the Great Blue Heron is most often listed on checklists started between 5 and 7 am (14% of those checklists).

0%5%10%15%12 am: too few checklists (510) to judge1 am: too few checklists (517) to judge2 am: too few checklists (581) to judge3 am: too few checklists (3242) to judge4 am: too few checklists (7221) to judge5 am: 14% of 19895 checklists6 am: 14% of 54578 checklists7 am: 11% of 92775 checklists8 am: 10% of 86962 checklists9 am: 9.0% of 78989 checklists10 am: 8.3% of 70954 checklists11 am: 7.3% of 59331 checklists12 pm: 6.9% of 50943 checklists1 pm: 7.1% of 49775 checklists2 pm: 7.1% of 49001 checklists3 pm: 7.8% of 43252 checklists4 pm: 9.8% of 33413 checklists5 pm: 12% of 25547 checklists6 pm: 12% of 18309 checklists7 pm: too few checklists (14287) to judge8 pm: too few checklists (5336) to judge9 pm: too few checklists (2253) to judge10 pm: too few checklists (1518) to judge11 pm: too few checklists (720) 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
January0.9%0.8%0.4%0.4%
February0.1%0.3%0.2%0.3%
March0.4%0.4%0.9%2.2%
April6.2%8.0%7.8%7.6%
May7.1%6.6%7.5%6.9%
June6.4%6.9%7.8%7.8%
July9.3%12%15%18%
August20%21%22%23%
September22%22%22%20%
October19%18%16%13%
November11%7.4%5.8%4.1%
December2.3%2.1%1.6%0.9%

Neighboring states

  • New Hampshire: arrives the second week of March, 1 week earlier than Maine
  • Massachusetts: arrives the second week of April, 3 weeks later than Maine
  • Vermont: arrives mid March, in the same week than Maine
  • Rhode Island: arrives early July, 14 weeks later than Maine

Common questions

When do Great Blue Herons arrive in Maine?
Great Blue Herons reach Maine in mid March, are common by the second week of April, peak in early September (23% of checklists), and most are gone by the second week of November.
When do Great Blue Herons leave Maine?
Most Great Blue Herons have left Maine by the second week of November, when reports fall below half their usual rate. Stragglers are still reported until mid December.
When is the best time to see a Great Blue Heron in Maine?
The Great Blue Heron is reported most often in early September, on about 23% of Maine checklists.
Where in Maine are Great Blue Herons seen most often?
By county, Knox County, Waldo County, and York County have the highest peak reporting rates for the Great Blue Heron (counties with at least 200 checklists).