WhenToBird

Bubo virginianus · Strigidae

When Do Great Horned Owls Arrive in Massachusetts?

Adult Great Horned Owl
Photo: Michael Warner, CC BY 4.0 via iNaturalist

Great Horned Owls are winter birds in Massachusetts: they arrive in mid August, peak in late December (1.6% of checklists), and most are gone by late May.

When to look

First arrivalsAug 15-21mid August
Common byAug 15-21mid August
PeakDec 22-31late December
Most gone byMay 22-31late May

Best: late December. First arrivals mid August; most are gone by late May. Peak: on about 1.6% of Massachusetts checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Jununcommon
  7. Juluncommon
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novcommon
  12. Decpeak season

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

0%0.5%1%1.5%2%Jan 1-7: 1.4% of 43252 checklistsJan 8-14: 1.2% of 30096 checklistsJan 15-21: 1.1% of 28760 checklistsJan 22-31: 1.2% of 38135 checklistsFeb 1-7: 0.9% of 26442 checklistsFeb 8-14: 1.0% of 29034 checklistsFeb 15-21: 0.9% of 37383 checklistsFeb 22-28: 1.0% of 29977 checklistsMar 1-7: 1.0% of 29175 checklistsMar 8-14: 1.0% of 32399 checklistsMar 15-21: 1.1% of 34444 checklistsMar 22-31: 1.0% of 49126 checklistsApr 1-7: 0.9% of 36456 checklistsApr 8-14: 0.9% of 40908 checklistsApr 15-21: 0.9% of 42078 checklistsApr 22-30: 1.0% of 56465 checklistsMay 1-7: 1.0% of 56994 checklistsMay 8-14: 0.9% of 64079 checklistsMay 15-21: 0.8% of 52020 checklistsMay 22-31: 0.5% of 55402 checklistsJun 1-7: 0.4% of 30682 checklistsJun 8-14: 0.4% of 27557 checklistsJun 15-21: 0.3% of 26163 checklistsJun 22-30: 0.3% of 29576 checklistsJul 1-7: 0.3% of 23931 checklistsJul 8-14: 0.3% of 22389 checklistsJul 15-21: 0.4% of 22365 checklistsJul 22-31: 0.4% of 32631 checklistsAug 1-7: 0.5% of 25133 checklistsAug 8-14: 0.4% of 24610 checklistsAug 15-21: 0.5% of 25350 checklistsAug 22-31: 0.7% of 37198 checklistsSep 1-7: 0.8% of 27402 checklistsSep 8-14: 0.8% of 27700 checklistsSep 15-21: 1.1% of 28398 checklistsSep 22-30: 1.1% of 34646 checklistsOct 1-7: 1.1% of 28620 checklistsOct 8-14: 1.0% of 30144 checklistsOct 15-21: 1.0% of 28893 checklistsOct 22-31: 1.0% of 38869 checklistsNov 1-7: 0.9% of 29782 checklistsNov 8-14: 0.9% of 27582 checklistsNov 15-21: 0.9% of 26642 checklistsNov 22-30: 1.0% of 34390 checklistsDec 1-7: 1.1% of 25164 checklistsDec 8-14: 1.2% of 24892 checklistsDec 15-21: 1.7% of 29022 checklistsDec 22-31: 1.7% of 44323 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 Massachusetts 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 Massachusetts

Best counties

Share of checklists at the peak
  1. Middlesex CountyBest late December · 7846 checklists that week, 307,511 in all2.4%
  2. Suffolk CountyBest the second week of March · 2116 checklists that week, 112,443 in all2.4%
  3. Barnstable CountyBest mid December · 3672 checklists that week, 215,188 in all2.3%
  4. Hampshire CountyBest the second week of January · 2793 checklists that week, 162,423 in all2.2%
  5. Plymouth CountyBest late September · 1977 checklists that week, 89,282 in all2.1%
  6. Hampden CountyBest mid December · 488 checklists that week, 35,410 in all1.9%

Best spots

Share of checklists at the peak
  1. Holt HillEssex County, best the second week of May · 24 checklists that week, 340 in all52%
  2. Mill PondMiddlesex County, best the second week of January · 29 checklists that week, 1,293 in all38%
  3. Coldspring ParkMiddlesex County, best early December · 25 checklists that week, 2,233 in all34%
  4. Chandlers Far DivisionEssex County, best early March · 24 checklists that week, 738 in all28%
  5. Mildred Morse Allen Wildlife SanctuaryNorfolk County, best early May · 27 checklists that week, 517 in all27%

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

Best time of day

In Massachusetts, the Great Horned Owl is most often listed on checklists started between 5 and 7 pm (1.7% of those checklists).

0%0.5%1%1.5%2%12 am: too few checklists (630) to judge1 am: too few checklists (657) to judge2 am: too few checklists (645) to judge3 am: too few checklists (850) to judge4 am: too few checklists (3787) to judge5 am: too few checklists (29743) to judge6 am: 1.8% of 108601 checklists7 am: 0.5% of 186104 checklists8 am: 0.4% of 185905 checklists9 am: 0.3% of 166049 checklists10 am: 0.4% of 150508 checklists11 am: 0.3% of 131024 checklists12 pm: 0.3% of 116804 checklists1 pm: 0.4% of 112055 checklists2 pm: 0.6% of 110246 checklists3 pm: 0.9% of 104376 checklists4 pm: 1.5% of 83736 checklists5 pm: 1.6% of 63723 checklists6 pm: 1.9% of 41435 checklists7 pm: too few checklists (21041) to judge8 pm: too few checklists (5240) to judge9 pm: too few checklists (1722) to judge10 pm: too few checklists (1094) to judge11 pm: too few checklists (704) 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
January1.4%1.2%1.1%1.2%
February0.9%1.0%0.9%1.0%
March1.0%1.0%1.1%1.0%
April0.9%0.9%0.9%1.0%
May1.0%0.9%0.8%0.5%
June0.4%0.4%0.3%0.3%
July0.3%0.3%0.4%0.4%
August0.5%0.4%0.5%0.7%
September0.8%0.8%1.1%1.1%
October1.1%1.0%1.0%1.0%
November0.9%0.9%0.9%1.0%
December1.1%1.2%1.7%1.7%

Neighboring states

  • Rhode Island: arrives mid August, in the same week than Massachusetts
  • Connecticut: arrives the second week of August, 1 week earlier than Massachusetts
  • New York: arrives mid August, in the same week than Massachusetts
  • New Jersey: arrives mid August, in the same week than Massachusetts

Common questions

When do Great Horned Owls arrive in Massachusetts?
Great Horned Owls are winter birds in Massachusetts: they arrive in mid August, peak in late December (1.6% of checklists), and most are gone by late May.
When do Great Horned Owls leave Massachusetts?
Most Great Horned Owls have left Massachusetts by late May, when reports fall below half their usual rate.
When is the best time to see a Great Horned Owl in Massachusetts?
The Great Horned Owl is reported most often in late December, on about 1.6% of Massachusetts checklists.
Where in Massachusetts are Great Horned Owls seen most often?
By county, Middlesex County, Suffolk County, and Barnstable County have the highest peak reporting rates for the Great Horned Owl (counties with at least 200 checklists).