WhenToBird

Bubo virginianus · Strigidae

When Do Great Horned Owls Arrive in Maryland?

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

Great Horned Owls are winter birds in Maryland: they arrive in the second week of August, peak in late December (1.3% of checklists), and most are gone by mid May.

When to look

First arrivalsAug 8-14the second week of August
Common byAug 8-14the second week of August
PeakDec 22-31late December
Most gone byMay 15-21mid May

Best: late December. First arrivals the second week of August; most are gone by mid May. Peak: on about 1.3% of Maryland checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  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%Jan 1-7: 1.0% of 28716 checklistsJan 8-14: 0.8% of 21449 checklistsJan 15-21: 0.8% of 21267 checklistsJan 22-31: 1.1% of 29144 checklistsFeb 1-7: 1.2% of 21347 checklistsFeb 8-14: 0.9% of 22166 checklistsFeb 15-21: 0.9% of 29986 checklistsFeb 22-28: 1.2% of 22427 checklistsMar 1-7: 1.2% of 21389 checklistsMar 8-14: 1.1% of 22192 checklistsMar 15-21: 1.2% of 22823 checklistsMar 22-31: 1.0% of 33720 checklistsApr 1-7: 1.0% of 25513 checklistsApr 8-14: 0.8% of 27718 checklistsApr 15-21: 0.7% of 29328 checklistsApr 22-30: 0.6% of 42595 checklistsMay 1-7: 0.5% of 38532 checklistsMay 8-14: 0.6% of 42722 checklistsMay 15-21: 0.4% of 31936 checklistsMay 22-31: 0.4% of 36903 checklistsJun 1-7: 0.3% of 23191 checklistsJun 8-14: 0.5% of 21853 checklistsJun 15-21: 0.4% of 21000 checklistsJun 22-30: 0.4% of 25133 checklistsJul 1-7: 0.3% of 18715 checklistsJul 8-14: 0.3% of 16376 checklistsJul 15-21: 0.3% of 15793 checklistsJul 22-31: 0.3% of 21969 checklistsAug 1-7: 0.3% of 16013 checklistsAug 8-14: 0.5% of 15249 checklistsAug 15-21: 0.5% of 15674 checklistsAug 22-31: 0.6% of 24925 checklistsSep 1-7: 0.6% of 19808 checklistsSep 8-14: 0.6% of 18513 checklistsSep 15-21: 0.8% of 21901 checklistsSep 22-30: 0.8% of 22901 checklistsOct 1-7: 0.9% of 19111 checklistsOct 8-14: 0.9% of 18482 checklistsOct 15-21: 0.8% of 17380 checklistsOct 22-31: 0.8% of 23992 checklistsNov 1-7: 0.9% of 17915 checklistsNov 8-14: 0.9% of 18905 checklistsNov 15-21: 0.6% of 16259 checklistsNov 22-30: 0.7% of 22852 checklistsDec 1-7: 0.7% of 16108 checklistsDec 8-14: 0.6% of 16512 checklistsDec 15-21: 1.5% of 18952 checklistsDec 22-31: 1.4% of 29728 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 Maryland 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 Maryland

Best counties

Share of checklists at the peak
  1. Somerset CountyBest mid December · 72 checklists that week, 9,451 in all7.7%
  2. Kent CountyBest mid December · 568 checklists that week, 13,396 in all5.6%
  3. Queen Anne's CountyBest early April · 549 checklists that week, 26,875 in all5.3%
  4. Talbot CountyBest late December · 563 checklists that week, 31,140 in all4.5%
  5. Dorchester CountyBest late March · 641 checklists that week, 26,161 in all4.3%
  6. St. Mary's CountyBest the second week of December · 348 checklists that week, 20,572 in all3.8%

Best spots

Share of checklists at the peak
  1. Lake Needwood (North Branch Rock Creek)Montgomery County, best mid March · 49 checklists that week, 2,257 in all48%
  2. Fairmount WmaSomerset County, best late December · 24 checklists that week, 123 in all43%
  3. Marshy CreekQueen Anne's County, best the second week of April · 69 checklists that week, 3,190 in all24%
  4. ElliotFrederick County, best mid April · 22 checklists that week, 549 in all18%

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

Best time of day

In Maryland, the Great Horned Owl is most often listed on checklists started between 5 and 7 pm (1.4% of those checklists).

0%1%2%3%12 am: too few checklists (486) to judge1 am: too few checklists (451) to judge2 am: too few checklists (447) to judge3 am: too few checklists (766) to judge4 am: too few checklists (2076) to judge5 am: too few checklists (11098) to judge6 am: 2.0% of 56604 checklists7 am: 0.5% of 139255 checklists8 am: 0.4% of 148626 checklists9 am: 0.3% of 126820 checklists10 am: 0.3% of 106973 checklists11 am: 0.2% of 87483 checklists12 pm: 0.3% of 74808 checklists1 pm: 0.3% of 69428 checklists2 pm: 0.4% of 67800 checklists3 pm: 0.7% of 67688 checklists4 pm: 1.2% of 60927 checklists5 pm: 1.4% of 43876 checklists6 pm: 1.4% of 32930 checklists7 pm: too few checklists (19051) to judge8 pm: too few checklists (5708) to judge9 pm: too few checklists (1977) to judge10 pm: too few checklists (1170) to judge11 pm: too few checklists (635) 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
January1.0%0.8%0.8%1.1%
February1.2%0.9%0.9%1.2%
March1.2%1.1%1.2%1.0%
April1.0%0.8%0.7%0.6%
May0.5%0.6%0.4%0.4%
June0.3%0.5%0.4%0.4%
July0.3%0.3%0.3%0.3%
August0.3%0.5%0.5%0.6%
September0.6%0.6%0.8%0.8%
October0.9%0.9%0.8%0.8%
November0.9%0.9%0.6%0.7%
December0.7%0.6%1.5%1.4%

Neighboring states

  • Delaware: arrives mid August, 1 week later than Maryland
  • Pennsylvania: arrives late August, 2 weeks later than Maryland
  • New Jersey: arrives mid August, 1 week later than Maryland
  • New York: arrives mid August, 1 week later than Maryland

Common questions

When do Great Horned Owls arrive in Maryland?
Great Horned Owls are winter birds in Maryland: they arrive in the second week of August, peak in late December (1.3% of checklists), and most are gone by mid May.
When do Great Horned Owls leave Maryland?
Most Great Horned Owls have left Maryland by mid May, when reports fall below half their usual rate.
When is the best time to see a Great Horned Owl in Maryland?
The Great Horned Owl is reported most often in late December, on about 1.3% of Maryland checklists.
Where in Maryland are Great Horned Owls seen most often?
By county, Somerset County, Kent County, and Queen Anne's County have the highest peak reporting rates for the Great Horned Owl (counties with at least 200 checklists).