WhenToBird

Phalacrocorax carbo · Phalacrocoracidae

When Do Great Cormorants Arrive in Maine?

Adult Great Cormorant
Photo: bemma, CC BY 4.0 via iNaturalist

Great Cormorants are winter birds in Maine: the first arrive in the second week of September, they are common by late September, peak in the second week of January (4.6% of checklists), and most are gone by mid March.

When to look

First arrivalsSep 8-14the second week of September
Common bySep 22-30late September
PeakJan 8-14the second week of January
Most gone byMar 15-21mid March

Best: the second week of January. First arrivals the second week of September; most are gone by mid March. Peak: on about 4.6% of Maine checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Apruncommon
  5. Mayrare
  6. Junrare
  7. Julrare
  8. Auguncommon
  9. Sepuncommon
  10. Octuncommon
  11. Novcommon
  12. Decpeak season

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

0%2%4%6%Jan 1-7: 4.7% of 15499 checklistsJan 8-14: 4.6% of 11141 checklistsJan 15-21: 4.5% of 10729 checklistsJan 22-31: 4.5% of 15084 checklistsFeb 1-7: 3.7% of 9403 checklistsFeb 8-14: 3.8% of 11268 checklistsFeb 15-21: 3.2% of 14061 checklistsFeb 22-28: 3.8% of 9977 checklistsMar 1-7: 2.8% of 9649 checklistsMar 8-14: 2.5% of 11781 checklistsMar 15-21: 1.6% of 11613 checklistsMar 22-31: 1.4% of 17798 checklistsApr 1-7: 0.9% of 14638 checklistsApr 8-14: 0.5% of 16511 checklistsApr 15-21: 0.5% of 17164 checklistsApr 22-30: 0.3% of 22602 checklistsMay 1-7: 0.3% of 22556 checklistsMay 8-14: 0.2% of 27842 checklistsMay 15-21: 0.3% of 27748 checklistsMay 22-31: 0.4% of 38715 checklistsJun 1-7: 0.4% of 26916 checklistsJun 8-14: 0.3% of 23737 checklistsJun 15-21: 0.4% of 22733 checklistsJun 22-30: 0.3% of 28248 checklistsJul 1-7: 0.3% of 20290 checklistsJul 8-14: 0.4% of 18534 checklistsJul 15-21: 0.3% of 17319 checklistsJul 22-31: 0.4% of 22815 checklistsAug 1-7: 0.3% of 15004 checklistsAug 8-14: 0.5% of 14603 checklistsAug 15-21: 0.6% of 14972 checklistsAug 22-31: 0.6% of 19813 checklistsSep 1-7: 0.9% of 14567 checklistsSep 8-14: 1.3% of 14520 checklistsSep 15-21: 1.4% of 14339 checklistsSep 22-30: 1.7% of 16879 checklistsOct 1-7: 1.5% of 12959 checklistsOct 8-14: 1.5% of 13168 checklistsOct 15-21: 1.4% of 11184 checklistsOct 22-31: 1.5% of 13717 checklistsNov 1-7: 1.9% of 9823 checklistsNov 8-14: 2.7% of 9007 checklistsNov 15-21: 2.4% of 8528 checklistsNov 22-30: 3.0% of 10228 checklistsDec 1-7: 4.2% of 7505 checklistsDec 8-14: 3.5% of 7982 checklistsDec 15-21: 3.5% of 10455 checklistsDec 22-31: 4.1% 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. York CountyBest mid January · 1645 checklists that week, 101,844 in all12%
  2. Sagadahoc CountyBest mid December · 335 checklists that week, 21,736 in all8.8%
  3. Hancock CountyBest the second week of January · 1558 checklists that week, 118,358 in all6.8%
  4. Washington CountyBest mid January · 202 checklists that week, 35,967 in all6.1%
  5. Cumberland CountyBest late January · 3905 checklists that week, 169,501 in all4.6%
  6. Lincoln CountyBest late September · 2193 checklists that week, 59,429 in all4.0%

Best spots

Share of checklists at the peak
  1. South PointYork County, best the second week of January · 31 checklists that week, 1,022 in all78%
  2. East PondHancock County, best late February · 34 checklists that week, 690 in all75%
  3. Nubble Light and Sohier ParkYork County, best the second week of January · 84 checklists that week, 2,150 in all74%
  4. Seal IslandKnox County, best late July · 36 checklists that week, 206 in all68%
  5. East Point Audubon SanctuaryYork County, best the second week of January · 79 checklists that week, 2,338 in all63%
  6. Seawall PondHancock County, best mid February · 30 checklists that week, 1,604 in all61%

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

Best time of day

In Maine, the Great Cormorant is most often listed on checklists started between 1 and 3 pm (2.3% of those checklists).

0%1%2%3%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: 0.6% of 19895 checklists6 am: 1.2% of 54578 checklists7 am: 0.8% of 92775 checklists8 am: 1.1% of 86962 checklists9 am: 1.4% of 78989 checklists10 am: 1.8% of 70954 checklists11 am: 2.1% of 59331 checklists12 pm: 2.1% of 50943 checklists1 pm: 2.2% of 49775 checklists2 pm: 2.3% of 49001 checklists3 pm: 1.6% of 43252 checklists4 pm: 1.1% of 33413 checklists5 pm: 0.6% of 25547 checklists6 pm: 0.3% 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
January4.7%4.6%4.5%4.5%
February3.7%3.8%3.2%3.8%
March2.8%2.5%1.6%1.4%
April0.9%0.5%0.5%0.3%
May0.3%0.2%0.3%0.4%
June0.4%0.3%0.4%0.3%
July0.3%0.4%0.3%0.4%
August0.3%0.5%0.6%0.6%
September0.9%1.3%1.4%1.7%
October1.5%1.5%1.4%1.5%
November1.9%2.7%2.4%3.0%
December4.2%3.5%3.5%4.1%

Neighboring states

  • New Hampshire: arrives the second week of September, in the same week than Maine
  • Massachusetts: arrives early October, 3 weeks later than Maine
  • Rhode Island: arrives the second week of September, in the same week than Maine
  • Connecticut: arrives mid November, 9 weeks later than Maine

Common questions

When do Great Cormorants arrive in Maine?
Great Cormorants are winter birds in Maine: the first arrive in the second week of September, they are common by late September, peak in the second week of January (4.6% of checklists), and most are gone by mid March.
When do Great Cormorants leave Maine?
Most Great Cormorants have left Maine by mid March, when reports fall below half their usual rate. Stragglers are still reported until late March.
When is the best time to see a Great Cormorant in Maine?
The Great Cormorant is reported most often in the second week of January, on about 4.6% of Maine checklists.
Where in Maine are Great Cormorants seen most often?
By county, York County, Sagadahoc County, and Hancock County have the highest peak reporting rates for the Great Cormorant (counties with at least 200 checklists).