WhenToBird

Larus marinus · Laridae

When Do Great Black-backed Gulls Arrive in Connecticut?

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

Great Black-backed Gulls are in Connecticut all year, but most are here in summer: numbers build from early July, peak in the second week of August (13% of checklists), and fall back by the second week of September. In the quietest week (early May) they are still on about 3.9% of checklists.

When to look

Numbers buildJul 1-7early July
PeakAug 8-14the second week of August
Fall back bySep 8-14the second week of September
FewestMay 1-7early May

Best: the second week of August. Here all year; numbers build from early July and fall back by the second week of September. Peak: on about 13% of Connecticut checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marcommon
  4. Aprcommon
  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%15%Jan 1-7: 12% of 18950 checklistsJan 8-14: 12% of 13676 checklistsJan 15-21: 12% of 13377 checklistsJan 22-31: 11% of 17004 checklistsFeb 1-7: 11% of 10218 checklistsFeb 8-14: 9.2% of 11568 checklistsFeb 15-21: 7.2% of 15916 checklistsFeb 22-28: 8.5% of 11413 checklistsMar 1-7: 9.3% of 10754 checklistsMar 8-14: 8.5% of 12051 checklistsMar 15-21: 9.1% of 12616 checklistsMar 22-31: 9.0% of 17801 checklistsApr 1-7: 8.9% of 13186 checklistsApr 8-14: 7.2% of 14428 checklistsApr 15-21: 6.2% of 14738 checklistsApr 22-30: 3.9% of 21753 checklistsMay 1-7: 3.7% of 22494 checklistsMay 8-14: 4.0% of 23363 checklistsMay 15-21: 4.8% of 20219 checklistsMay 22-31: 6.6% of 20778 checklistsJun 1-7: 7.6% of 12234 checklistsJun 8-14: 7.3% of 12491 checklistsJun 15-21: 6.9% of 10856 checklistsJun 22-30: 8.2% of 11964 checklistsJul 1-7: 8.4% of 9437 checklistsJul 8-14: 10% of 8599 checklistsJul 15-21: 12% of 8252 checklistsJul 22-31: 13% of 11329 checklistsAug 1-7: 13% of 8116 checklistsAug 8-14: 13% of 8051 checklistsAug 15-21: 13% of 8502 checklistsAug 22-31: 11% of 13673 checklistsSep 1-7: 11% of 9873 checklistsSep 8-14: 8.8% of 9735 checklistsSep 15-21: 7.6% of 10120 checklistsSep 22-30: 7.7% of 12543 checklistsOct 1-7: 6.5% of 10735 checklistsOct 8-14: 6.8% of 10869 checklistsOct 15-21: 6.4% of 10436 checklistsOct 22-31: 8.1% of 13808 checklistsNov 1-7: 8.5% of 10507 checklistsNov 8-14: 9.6% of 9827 checklistsNov 15-21: 8.8% of 9904 checklistsNov 22-30: 9.0% of 13396 checklistsDec 1-7: 9.4% of 8974 checklistsDec 8-14: 9.2% of 9468 checklistsDec 15-21: 8.6% of 11614 checklistsDec 22-31: 11% of 16616 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 Connecticut 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 Connecticut

Best counties

Share of checklists at the peak
  1. New Haven CountyBest the second week of August · 1918 checklists that week, 139,721 in all28%
  2. New London CountyBest mid January · 1490 checklists that week, 65,205 in all25%
  3. Fairfield CountyBest mid January · 3646 checklists that week, 139,848 in all20%
  4. Middlesex CountyBest the second week of August · 513 checklists that week, 39,919 in all10%
  5. Windham CountyBest the second week of December · 237 checklists that week, 19,034 in all4.5%
  6. Hartford CountyBest mid January · 2713 checklists that week, 105,735 in all3.6%

Best spots

Share of checklists at the peak
  1. Cedar PointFairfield County, best late July · 29 checklists that week, 1,206 in all95%
  2. Seaside ParkFairfield County, best the second week of November · 33 checklists that week, 1,151 in all90%
  3. Short BeachFairfield County, best the second week of August · 25 checklists that week, 1,711 in all87%
  4. Town Open Space (High Street)New London County, best early December · 21 checklists that week, 742 in all87%
  5. Ocean Beach ParkNew London County, best mid March · 22 checklists that week, 569 in all87%
  6. Stonington PointNew London County, best late November · 37 checklists that week, 1,092 in all82%

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

Best time of day

In Connecticut, the Great Black-backed Gull is most often listed on checklists started between 1 and 3 pm (10% of those checklists).

0%5%10%15%12 am: too few checklists (325) to judge1 am: too few checklists (367) to judge2 am: too few checklists (488) to judge3 am: too few checklists (792) to judge4 am: too few checklists (2722) to judge5 am: too few checklists (9489) to judge6 am: 6.3% of 33657 checklists7 am: 7.1% of 62964 checklists8 am: 8.7% of 70645 checklists9 am: 9.2% of 64870 checklists10 am: 9.7% of 58827 checklists11 am: 9.9% of 51689 checklists12 pm: 9.8% of 45288 checklists1 pm: 10% of 44765 checklists2 pm: 10% of 44173 checklists3 pm: 9.2% of 41979 checklists4 pm: 7.3% of 33219 checklists5 pm: 6.1% of 24828 checklists6 pm: 5.2% of 15856 checklists7 pm: too few checklists (8126) to judge8 pm: too few checklists (1994) to judge9 pm: too few checklists (533) to judge10 pm: too few checklists (349) to judge11 pm: too few checklists (286) 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
January12%12%12%11%
February11%9.2%7.2%8.5%
March9.3%8.5%9.1%9.0%
April8.9%7.2%6.2%3.9%
May3.7%4.0%4.8%6.6%
June7.6%7.3%6.9%8.2%
July8.4%10%12%13%
August13%13%13%11%
September11%8.8%7.6%7.7%
October6.5%6.8%6.4%8.1%
November8.5%9.6%8.8%9.0%
December9.4%9.2%8.6%11%

Neighboring states

  • Rhode Island: arrives mid June, 2 weeks earlier than Connecticut
  • Massachusetts: year-round, peaks the second week of August
  • New Jersey: year-round, peaks mid January
  • New York: arrives early November, 16 weeks later than Connecticut

Common questions

When do Great Black-backed Gulls arrive in Connecticut?
Great Black-backed Gulls are in Connecticut all year, but most are here in summer: numbers build from early July, peak in the second week of August (13% of checklists), and fall back by the second week of September. In the quietest week (early May) they are still on about 3.9% of checklists.
When do Great Black-backed Gulls leave Connecticut?
Great Black-backed Gulls never fully leave Connecticut: numbers fall back below half their usual rate by the second week of September, but some are still reported in every week, about 3.9% of checklists at the low.
When is the best time to see a Great Black-backed Gull in Connecticut?
The Great Black-backed Gull is reported most often in the second week of August, on about 13% of Connecticut checklists.
Where in Connecticut are Great Black-backed Gulls seen most often?
By county, New Haven County, New London County, and Fairfield County have the highest peak reporting rates for the Great Black-backed Gull (counties with at least 200 checklists).