WhenToBird

Larus marinus · Laridae

When Do Great Black-backed Gulls Arrive in Maine?

Adult Great Black-backed Gull
Photo: Rob Wadsworth, CC0 1.0 via iNaturalist

Great Black-backed Gulls are in Maine all year, but most are here in fall: numbers build from the second week of July, peak in the second week of August (18% of checklists), and fall back by late November. In the quietest week (mid April) they are still on about 6.1% of checklists.

When to look

Numbers buildJul 8-14the second week of July
PeakAug 8-14the second week of August
Fall back byNov 22-30late November
FewestApr 15-21mid April

Best: the second week of August. Here all year; numbers build from the second week of July and fall back by late November. Peak: on about 18% of Maine checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%5%10%15%20%Jan 1-7: 10% of 15499 checklistsJan 8-14: 9.7% of 11141 checklistsJan 15-21: 8.6% of 10729 checklistsJan 22-31: 9.3% of 15084 checklistsFeb 1-7: 8.0% of 9403 checklistsFeb 8-14: 7.4% of 11268 checklistsFeb 15-21: 7.2% of 14061 checklistsFeb 22-28: 9.0% of 9977 checklistsMar 1-7: 8.1% of 9649 checklistsMar 8-14: 7.2% of 11781 checklistsMar 15-21: 6.8% of 11613 checklistsMar 22-31: 6.5% of 17798 checklistsApr 1-7: 6.0% of 14638 checklistsApr 8-14: 6.3% of 16511 checklistsApr 15-21: 6.2% of 17164 checklistsApr 22-30: 6.0% of 22602 checklistsMay 1-7: 6.8% of 22556 checklistsMay 8-14: 6.1% of 27842 checklistsMay 15-21: 8.3% of 27748 checklistsMay 22-31: 10% of 38715 checklistsJun 1-7: 10% of 26916 checklistsJun 8-14: 9.1% of 23737 checklistsJun 15-21: 10% of 22733 checklistsJun 22-30: 9.2% of 28248 checklistsJul 1-7: 12% of 20290 checklistsJul 8-14: 13% of 18534 checklistsJul 15-21: 14% of 17319 checklistsJul 22-31: 15% of 22815 checklistsAug 1-7: 17% of 15004 checklistsAug 8-14: 18% of 14603 checklistsAug 15-21: 18% of 14972 checklistsAug 22-31: 16% of 19813 checklistsSep 1-7: 16% of 14567 checklistsSep 8-14: 17% of 14520 checklistsSep 15-21: 17% of 14339 checklistsSep 22-30: 18% of 16879 checklistsOct 1-7: 14% of 12959 checklistsOct 8-14: 15% of 13168 checklistsOct 15-21: 14% of 11184 checklistsOct 22-31: 14% of 13717 checklistsNov 1-7: 15% of 9823 checklistsNov 8-14: 14% of 9007 checklistsNov 15-21: 12% of 8528 checklistsNov 22-30: 12% of 10228 checklistsDec 1-7: 12% of 7505 checklistsDec 8-14: 10% of 7982 checklistsDec 15-21: 9.3% of 10455 checklistsDec 22-31: 9.4% 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 late August · 2683 checklists that week, 101,844 in all38%
  2. Lincoln CountyBest late September · 2193 checklists that week, 59,429 in all34%
  3. Sagadahoc CountyBest mid July · 500 checklists that week, 21,736 in all30%
  4. Washington CountyBest the second week of August · 1034 checklists that week, 35,967 in all28%
  5. Knox CountyBest mid July · 792 checklists that week, 34,453 in all27%
  6. Hancock CountyBest mid October · 1847 checklists that week, 118,358 in all21%

Best spots

Share of checklists at the peak
  1. Back BayYork County, best early October · 23 checklists that week, 1,607 in all97%
  2. Lighthouse CoveLincoln County, best mid September · 35 checklists that week, 1,298 in all93%
  3. Popham Beach State ParkSagadahoc County, best late September · 23 checklists that week, 749 in all93%
  4. Appledore IslandYork County, best the second week of June · 28 checklists that week, 422 in all92%

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

Best time of day

In Maine, the Great Black-backed Gull is most often listed on checklists started between 1 and 3 pm (13% of those checklists).

0%5%10%15%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: 9.6% of 19895 checklists6 am: 11% of 54578 checklists7 am: 9.2% of 92775 checklists8 am: 9.8% of 86962 checklists9 am: 11% of 78989 checklists10 am: 12% of 70954 checklists11 am: 12% of 59331 checklists12 pm: 13% of 50943 checklists1 pm: 13% of 49775 checklists2 pm: 13% of 49001 checklists3 pm: 12% of 43252 checklists4 pm: 12% of 33413 checklists5 pm: 12% of 25547 checklists6 pm: 10% 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
January10%9.7%8.6%9.3%
February8.0%7.4%7.2%9.0%
March8.1%7.2%6.8%6.5%
April6.0%6.3%6.2%6.0%
May6.8%6.1%8.3%10%
June10%9.1%10%9.2%
July12%13%14%15%
August17%18%18%16%
September16%17%17%18%
October14%15%14%14%
November15%14%12%12%
December12%10%9.3%9.4%

Neighboring states

  • New Hampshire: arrives late July, 2 weeks later than Maine
  • Massachusetts: year-round, peaks the second week of August
  • Vermont: arrives late July, 2 weeks later than Maine
  • Rhode Island: arrives mid June, 3 weeks earlier than Maine

Common questions

When do Great Black-backed Gulls arrive in Maine?
Great Black-backed Gulls are in Maine all year, but most are here in fall: numbers build from the second week of July, peak in the second week of August (18% of checklists), and fall back by late November. In the quietest week (mid April) they are still on about 6.1% of checklists.
When do Great Black-backed Gulls leave Maine?
Great Black-backed Gulls never fully leave Maine: numbers fall back below half their usual rate by late November, but some are still reported in every week, about 6.1% of checklists at the low.
When is the best time to see a Great Black-backed Gull in Maine?
The Great Black-backed Gull is reported most often in the second week of August, on about 18% of Maine checklists.
Where in Maine are Great Black-backed Gulls seen most often?
By county, York County, Lincoln County, and Sagadahoc County have the highest peak reporting rates for the Great Black-backed Gull (counties with at least 200 checklists).