WhenToBird

Nannopterum auritum · Phalacrocoracidae

When Do Double-crested Cormorants Arrive in Ohio?

Adult Double-crested Cormorant
Photo: jubileej, CC0 1.0 via iNaturalist

Double-crested Cormorants reach Ohio in late February, are common by mid March, peak in early September (24% of checklists), and most are gone by mid November.

When to look

First arrivalsFeb 22-28late February
Common byMar 15-21mid March
PeakSep 1-7early September
Most gone byNov 15-21mid November

Best: early September. First arrivals late February; most are gone by mid November. Peak: on about 24% of Ohio checklists.

  1. Janrare
  2. Febrare
  3. Marcommon
  4. Aprcommon
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decuncommon

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

0%10%20%30%Jan 1-7: 2.8% of 46637 checklistsJan 8-14: 2.3% of 31056 checklistsJan 15-21: 2.1% of 30129 checklistsJan 22-31: 2.3% of 38665 checklistsFeb 1-7: 1.3% of 27203 checklistsFeb 8-14: 1.2% of 30626 checklistsFeb 15-21: 1.1% of 40705 checklistsFeb 22-28: 2.2% of 31391 checklistsMar 1-7: 3.1% of 32914 checklistsMar 8-14: 4.3% of 33973 checklistsMar 15-21: 8.1% of 33678 checklistsMar 22-31: 12% of 49889 checklistsApr 1-7: 16% of 41225 checklistsApr 8-14: 16% of 47174 checklistsApr 15-21: 17% of 47017 checklistsApr 22-30: 16% of 73055 checklistsMay 1-7: 19% of 80637 checklistsMay 8-14: 22% of 102552 checklistsMay 15-21: 17% of 64582 checklistsMay 22-31: 13% of 52766 checklistsJun 1-7: 9.5% of 29279 checklistsJun 8-14: 9.1% of 25773 checklistsJun 15-21: 9.2% of 23163 checklistsJun 22-30: 9.6% of 27794 checklistsJul 1-7: 11% of 23334 checklistsJul 8-14: 11% of 22147 checklistsJul 15-21: 12% of 20998 checklistsJul 22-31: 14% of 29749 checklistsAug 1-7: 18% of 22899 checklistsAug 8-14: 20% of 21972 checklistsAug 15-21: 23% of 22215 checklistsAug 22-31: 25% of 35087 checklistsSep 1-7: 25% of 29148 checklistsSep 8-14: 24% of 28042 checklistsSep 15-21: 22% of 26751 checklistsSep 22-30: 22% of 32398 checklistsOct 1-7: 19% of 26209 checklistsOct 8-14: 17% of 26809 checklistsOct 15-21: 18% of 23504 checklistsOct 22-31: 18% of 33269 checklistsNov 1-7: 15% of 25563 checklistsNov 8-14: 11% of 23810 checklistsNov 15-21: 9.2% of 22127 checklistsNov 22-30: 6.3% of 29449 checklistsDec 1-7: 4.7% of 22370 checklistsDec 8-14: 3.5% of 21581 checklistsDec 15-21: 2.5% of 24232 checklistsDec 22-31: 2.1% of 36084 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 Ohio 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 Ohio

Best counties

Share of checklists at the peak
  1. Mercer CountyBest late September · 69 checklists that week, 2,091 in all71%
  2. Shelby CountyBest the second week of September · 34 checklists that week, 1,659 in all69%
  3. Ashtabula CountyBest late August · 424 checklists that week, 12,390 in all53%
  4. Erie CountyBest early September · 605 checklists that week, 30,456 in all53%
  5. Pickaway CountyBest early September · 135 checklists that week, 6,348 in all48%
  6. Muskingum CountyBest early September · 157 checklists that week, 9,849 in all45%

Best spots

Share of checklists at the peak
  1. East Fork State Park (Trimble Run)Clermont County, best mid August · 20 checklists that week, 282 in all100%
  2. Campbell Memorial ParkFranklin County, best early August · 24 checklists that week, 990 in all100%
  3. Lower NewportWashington County, best early January · 21 checklists that week, 466 in all98%
  4. Walbourne Reservoir (Walborn Reservoir)Stark County, best the second week of September · 30 checklists that week, 842 in all97%
  5. Hoover Reservoir Park (south 2)Delaware County, best the second week of October · 22 checklists that week, 1,072 in all97%

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

Best time of day

In Ohio, the Double-crested Cormorant 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 (574) to judge1 am: too few checklists (609) to judge2 am: too few checklists (466) to judge3 am: too few checklists (478) to judge4 am: too few checklists (662) to judge5 am: too few checklists (4366) to judge6 am: 17% of 43093 checklists7 am: 16% of 142017 checklists8 am: 13% of 205296 checklists9 am: 13% of 196322 checklists10 am: 12% of 170882 checklists11 am: 12% of 144567 checklists12 pm: 12% of 126551 checklists1 pm: 12% of 117855 checklists2 pm: 12% of 112869 checklists3 pm: 11% of 109786 checklists4 pm: 11% of 103116 checklists5 pm: 12% of 78409 checklists6 pm: 12% of 56785 checklists7 pm: 9.0% of 37923 checklists8 pm: too few checklists (14954) to judge9 pm: too few checklists (2710) to judge10 pm: too few checklists (854) to judge11 pm: too few checklists (486) 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
January2.8%2.3%2.1%2.3%
February1.3%1.2%1.1%2.2%
March3.1%4.3%8.1%12%
April16%16%17%16%
May19%22%17%13%
June9.5%9.1%9.2%9.6%
July11%11%12%14%
August18%20%23%25%
September25%24%22%22%
October19%17%18%18%
November15%11%9.2%6.3%
December4.7%3.5%2.5%2.1%

Neighboring states

  • West Virginia: arrives early July, 17 weeks later than Ohio
  • Indiana: arrives late February, in the same week than Ohio
  • Michigan: arrives mid March, 3 weeks later than Ohio
  • Kentucky: arrives late February, in the same week than Ohio

Common questions

When do Double-crested Cormorants arrive in Ohio?
Double-crested Cormorants reach Ohio in late February, are common by mid March, peak in early September (24% of checklists), and most are gone by mid November.
When do Double-crested Cormorants leave Ohio?
Most Double-crested Cormorants have left Ohio by mid November, when reports fall below half their usual rate. Stragglers are still reported until early February.
When is the best time to see a Double-crested Cormorant in Ohio?
The Double-crested Cormorant is reported most often in early September, on about 24% of Ohio checklists.
Where in Ohio are Double-crested Cormorants seen most often?
By county, Mercer County, Shelby County, and Ashtabula County have the highest peak reporting rates for the Double-crested Cormorant (counties with at least 200 checklists).