WhenToBird

Ardea herodias · Ardeidae

When Do Great Blue Herons Arrive in Connecticut?

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

Great Blue Herons are in Connecticut all year, but most are here in summer: numbers build from early May, peak in late August (22% of checklists), and fall back by late November. In the quietest week (mid February) they are still on about 5.1% of checklists.

When to look

Numbers buildMay 1-7early May
PeakAug 22-31late August
Fall back byNov 22-30late November
FewestFeb 15-21mid February

Best: late August. Here all year; numbers build from early May and fall back by late November. Peak: on about 22% of Connecticut checklists.

  1. Jancommon
  2. Febuncommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%10%20%30%Jan 1-7: 9.3% of 18950 checklistsJan 8-14: 8.8% of 13676 checklistsJan 15-21: 8.0% of 13377 checklistsJan 22-31: 7.9% of 17004 checklistsFeb 1-7: 6.4% of 10218 checklistsFeb 8-14: 5.6% of 11568 checklistsFeb 15-21: 4.5% of 15916 checklistsFeb 22-28: 5.5% of 11413 checklistsMar 1-7: 5.8% of 10754 checklistsMar 8-14: 6.2% of 12051 checklistsMar 15-21: 8.6% of 12616 checklistsMar 22-31: 11% of 17801 checklistsApr 1-7: 13% of 13186 checklistsApr 8-14: 13% of 14428 checklistsApr 15-21: 13% of 14738 checklistsApr 22-30: 14% of 21753 checklistsMay 1-7: 14% of 22494 checklistsMay 8-14: 14% of 23363 checklistsMay 15-21: 14% of 20219 checklistsMay 22-31: 14% of 20778 checklistsJun 1-7: 14% of 12234 checklistsJun 8-14: 15% of 12491 checklistsJun 15-21: 14% of 10856 checklistsJun 22-30: 13% of 11964 checklistsJul 1-7: 15% of 9437 checklistsJul 8-14: 18% of 8599 checklistsJul 15-21: 18% of 8252 checklistsJul 22-31: 20% of 11329 checklistsAug 1-7: 20% of 8116 checklistsAug 8-14: 20% of 8051 checklistsAug 15-21: 22% of 8502 checklistsAug 22-31: 23% of 13673 checklistsSep 1-7: 22% of 9873 checklistsSep 8-14: 22% of 9735 checklistsSep 15-21: 21% of 10120 checklistsSep 22-30: 21% of 12543 checklistsOct 1-7: 18% of 10735 checklistsOct 8-14: 17% of 10869 checklistsOct 15-21: 16% of 10436 checklistsOct 22-31: 16% of 13808 checklistsNov 1-7: 15% of 10507 checklistsNov 8-14: 14% of 9827 checklistsNov 15-21: 15% of 9904 checklistsNov 22-30: 15% of 13396 checklistsDec 1-7: 12% of 8974 checklistsDec 8-14: 11% of 9468 checklistsDec 15-21: 10% of 11614 checklistsDec 22-31: 9.7% of 16616 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 Connecticut 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 Connecticut

Best counties

Share of checklists at the peak
  1. Windham CountyBest late August · 396 checklists that week, 19,034 in all40%
  2. New London CountyBest mid September · 1000 checklists that week, 65,205 in all28%
  3. Litchfield CountyBest early September · 1115 checklists that week, 69,766 in all27%
  4. New Haven CountyBest early September · 2440 checklists that week, 139,721 in all24%
  5. Middlesex CountyBest early September · 627 checklists that week, 39,919 in all21%
  6. Fairfield CountyBest the second week of August · 1582 checklists that week, 139,848 in all21%

Best spots

Share of checklists at the peak
  1. Lake WhitneyNew Haven County, best early April · 25 checklists that week, 781 in all96%
  2. Mansfield Hollow LakeWindham County, best mid August · 67 checklists that week, 1,313 in all90%
  3. Rocky Neck State ParkNew London County, best the second week of December · 24 checklists that week, 1,526 in all90%
  4. Compo CoveFairfield County, best late September · 35 checklists that week, 368 in all89%
  5. Quinebaug Fish HatcheryWindham County, best mid May · 22 checklists that week, 1,048 in all89%
  6. Nod Brook Wildlife Management AreaHartford County, best late July · 36 checklists that week, 1,868 in all86%

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

Best time of day

In Connecticut, the Great Blue Heron is most often listed on checklists started between 6 and 8 am (16% of those checklists).

0%5%10%15%20%12 am: too few checklists (325) to judge1 am: too few checklists (367) to judge2 am: too few checklists (488) to judge3 am: too few checklists (792) to judge4 am: too few checklists (2722) to judge5 am: too few checklists (9489) to judge6 am: 19% of 33657 checklists7 am: 15% of 62964 checklists8 am: 15% of 70645 checklists9 am: 14% of 64870 checklists10 am: 13% of 58827 checklists11 am: 12% of 51689 checklists12 pm: 11% of 45288 checklists1 pm: 11% of 44765 checklists2 pm: 12% of 44173 checklists3 pm: 12% of 41979 checklists4 pm: 12% of 33219 checklists5 pm: 14% of 24828 checklists6 pm: 15% of 15856 checklists7 pm: too few checklists (8126) to judge8 pm: too few checklists (1994) to judge9 pm: too few checklists (533) to judge10 pm: too few checklists (349) to judge11 pm: too few checklists (286) 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
January9.3%8.8%8.0%7.9%
February6.4%5.6%4.5%5.5%
March5.8%6.2%8.6%11%
April13%13%13%14%
May14%14%14%14%
June14%15%14%13%
July15%18%18%20%
August20%20%22%23%
September22%22%21%21%
October18%17%16%16%
November15%14%15%15%
December12%11%10%9.7%

Neighboring states

  • Rhode Island: arrives early July, 8 weeks later than Connecticut
  • Massachusetts: arrives the second week of April, 3 weeks earlier than Connecticut
  • New Jersey: year-round, peaks early August
  • New York: arrives early July, 8 weeks later than Connecticut

Common questions

When do Great Blue Herons arrive in Connecticut?
Great Blue Herons are in Connecticut all year, but most are here in summer: numbers build from early May, peak in late August (22% of checklists), and fall back by late November. In the quietest week (mid February) they are still on about 5.1% of checklists.
When do Great Blue Herons leave Connecticut?
Great Blue Herons never fully leave Connecticut: numbers fall back below half their usual rate by late November, but some are still reported in every week, about 5.1% of checklists at the low.
When is the best time to see a Great Blue Heron in Connecticut?
The Great Blue Heron is reported most often in late August, on about 22% of Connecticut checklists.
Where in Connecticut are Great Blue Herons seen most often?
By county, Windham County, New London County, and Litchfield County have the highest peak reporting rates for the Great Blue Heron (counties with at least 200 checklists).