WhenToBird

Cepphus grylle · Alcidae

When Do Black Guillemots Arrive in Maine?

Adult Black Guillemot
Photo: Jo Roberts, CC BY 4.0 via iNaturalist

Black Guillemots reach Maine in the second week of May, are common by mid May, peak in the second week of August (7.7% of checklists), and most are gone by early March.

When to look

First arrivalsMay 8-14the second week of May
Common byMay 15-21mid May
PeakAug 8-14the second week of August
Most gone byMar 1-7early March

Best: the second week of August. First arrivals the second week of May; most are gone by early March. Peak: on about 7.7% of Maine checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octcommon
  11. Novcommon
  12. Decpeak season

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

0%5%10%Jan 1-7: 6.3% of 15499 checklistsJan 8-14: 5.8% of 11141 checklistsJan 15-21: 5.2% of 10729 checklistsJan 22-31: 5.4% of 15084 checklistsFeb 1-7: 4.3% of 9403 checklistsFeb 8-14: 4.6% of 11268 checklistsFeb 15-21: 3.4% of 14061 checklistsFeb 22-28: 4.4% of 9977 checklistsMar 1-7: 3.0% of 9649 checklistsMar 8-14: 3.6% of 11781 checklistsMar 15-21: 2.4% of 11613 checklistsMar 22-31: 1.9% of 17798 checklistsApr 1-7: 1.5% of 14638 checklistsApr 8-14: 1.5% of 16511 checklistsApr 15-21: 1.7% of 17164 checklistsApr 22-30: 1.5% of 22602 checklistsMay 1-7: 1.8% of 22556 checklistsMay 8-14: 2.1% of 27842 checklistsMay 15-21: 3.7% of 27748 checklistsMay 22-31: 5.2% of 38715 checklistsJun 1-7: 5.8% of 26916 checklistsJun 8-14: 4.5% of 23737 checklistsJun 15-21: 4.9% of 22733 checklistsJun 22-30: 4.0% of 28248 checklistsJul 1-7: 4.9% of 20290 checklistsJul 8-14: 5.6% of 18534 checklistsJul 15-21: 5.5% of 17319 checklistsJul 22-31: 5.8% of 22815 checklistsAug 1-7: 6.6% of 15004 checklistsAug 8-14: 8.4% of 14603 checklistsAug 15-21: 8.1% of 14972 checklistsAug 22-31: 6.7% of 19813 checklistsSep 1-7: 6.8% of 14567 checklistsSep 8-14: 6.9% of 14520 checklistsSep 15-21: 6.5% of 14339 checklistsSep 22-30: 5.9% of 16879 checklistsOct 1-7: 5.4% of 12959 checklistsOct 8-14: 5.4% of 13168 checklistsOct 15-21: 5.2% of 11184 checklistsOct 22-31: 4.7% of 13717 checklistsNov 1-7: 4.6% of 9823 checklistsNov 8-14: 4.5% of 9007 checklistsNov 15-21: 4.7% of 8528 checklistsNov 22-30: 5.1% of 10228 checklistsDec 1-7: 5.1% of 7505 checklistsDec 8-14: 5.2% of 7982 checklistsDec 15-21: 5.1% of 10455 checklistsDec 22-31: 5.8% 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. Knox CountyBest mid July · 792 checklists that week, 34,453 in all28%
  2. Lincoln CountyBest late May · 3553 checklists that week, 59,429 in all18%
  3. Sagadahoc CountyBest late December · 477 checklists that week, 21,736 in all17%
  4. Washington CountyBest the second week of August · 1034 checklists that week, 35,967 in all15%
  5. Waldo CountyBest late August · 860 checklists that week, 33,433 in all15%
  6. Hancock CountyBest mid August · 2564 checklists that week, 118,358 in all15%

Best spots

Share of checklists at the peak
  1. Eastern Egg RockKnox County, best the second week of July · 123 checklists that week, 1,346 in all98%
  2. Petit Manan IslandWashington County, best mid July · 47 checklists that week, 680 in all90%
  3. Egg RockHancock County, best late July · 22 checklists that week, 166 in all86%
  4. Five Mile HarborSagadahoc County, best the second week of February · 62 checklists that week, 543 in all79%
  5. Metinic IslandKnox County, best early July · 22 checklists that week, 263 in all79%
  6. Arey CoveHancock County, best late January · 32 checklists that week, 1,909 in all78%

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

Best time of day

In Maine, the Black Guillemot is most often listed on checklists started between 11 am and 1 pm (6.2% of those checklists).

0%2%4%6%8%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: 4.0% of 19895 checklists6 am: 4.8% of 54578 checklists7 am: 3.3% of 92775 checklists8 am: 3.4% of 86962 checklists9 am: 4.6% of 78989 checklists10 am: 5.5% of 70954 checklists11 am: 6.2% of 59331 checklists12 pm: 6.3% of 50943 checklists1 pm: 6.0% of 49775 checklists2 pm: 5.7% of 49001 checklists3 pm: 5.2% of 43252 checklists4 pm: 5.0% of 33413 checklists5 pm: 4.5% of 25547 checklists6 pm: 3.4% 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
January6.3%5.8%5.2%5.4%
February4.3%4.6%3.4%4.4%
March3.0%3.6%2.4%1.9%
April1.5%1.5%1.7%1.5%
May1.8%2.1%3.7%5.2%
June5.8%4.5%4.9%4.0%
July4.9%5.6%5.5%5.8%
August6.6%8.4%8.1%6.7%
September6.8%6.9%6.5%5.9%
October5.4%5.4%5.2%4.7%
November4.6%4.5%4.7%5.1%
December5.1%5.2%5.1%5.8%

Common questions

When do Black Guillemots arrive in Maine?
Black Guillemots reach Maine in the second week of May, are common by mid May, peak in the second week of August (7.7% of checklists), and most are gone by early March.
When do Black Guillemots leave Maine?
Most Black Guillemots have left Maine by early March, when reports fall below half their usual rate. Stragglers are still reported until mid March.
When is the best time to see a Black Guillemot in Maine?
The Black Guillemot is reported most often in the second week of August, on about 7.7% of Maine checklists.
Where in Maine are Black Guillemots seen most often?
By county, Knox County, Lincoln County, and Sagadahoc County have the highest peak reporting rates for the Black Guillemot (counties with at least 200 checklists).