WhenToBird

Larus marinus · Laridae

When Do Great Black-backed Gulls Arrive in New Hampshire?

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

Great Black-backed Gulls are in New Hampshire all year, but most are here in fall: numbers build from late July, peak in early December (8.0% of checklists), and fall back by late January. In the quietest week (mid June) they are still on about 3.0% of checklists.

When to look

Numbers buildJul 22-31late July
PeakDec 1-7early December
Fall back byJan 22-31late January
FewestJun 15-21mid June

Best: early December. Here all year; numbers build from late July and fall back by late January. Peak: on about 8.0% of New Hampshire checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%5%10%Jan 1-7: 8.1% of 8253 checklistsJan 8-14: 7.0% of 5998 checklistsJan 15-21: 6.2% of 5734 checklistsJan 22-31: 6.3% of 7776 checklistsFeb 1-7: 5.3% of 5253 checklistsFeb 8-14: 4.6% of 6802 checklistsFeb 15-21: 4.0% of 8852 checklistsFeb 22-28: 5.0% of 5792 checklistsMar 1-7: 5.1% of 6187 checklistsMar 8-14: 4.5% of 6977 checklistsMar 15-21: 3.9% of 7863 checklistsMar 22-31: 4.0% of 11746 checklistsApr 1-7: 3.4% of 9329 checklistsApr 8-14: 3.2% of 10499 checklistsApr 15-21: 2.7% of 10376 checklistsApr 22-30: 3.1% of 13086 checklistsMay 1-7: 3.1% of 13198 checklistsMay 8-14: 3.0% of 14980 checklistsMay 15-21: 3.5% of 12487 checklistsMay 22-31: 3.8% of 14294 checklistsJun 1-7: 3.5% of 8974 checklistsJun 8-14: 2.7% of 8395 checklistsJun 15-21: 3.0% of 7670 checklistsJun 22-30: 3.3% of 9188 checklistsJul 1-7: 3.1% of 7707 checklistsJul 8-14: 5.3% of 6554 checklistsJul 15-21: 4.9% of 6636 checklistsJul 22-31: 5.3% of 9599 checklistsAug 1-7: 6.8% of 6436 checklistsAug 8-14: 6.8% of 6477 checklistsAug 15-21: 7.4% of 6510 checklistsAug 22-31: 7.5% of 9762 checklistsSep 1-7: 7.2% of 6700 checklistsSep 8-14: 7.6% of 6012 checklistsSep 15-21: 7.1% of 6238 checklistsSep 22-30: 6.6% of 7619 checklistsOct 1-7: 5.7% of 6702 checklistsOct 8-14: 6.2% of 6863 checklistsOct 15-21: 7.0% of 6284 checklistsOct 22-31: 8.0% of 8287 checklistsNov 1-7: 8.0% of 7584 checklistsNov 8-14: 7.2% of 6056 checklistsNov 15-21: 6.7% of 5597 checklistsNov 22-30: 8.2% of 7140 checklistsDec 1-7: 7.7% of 4623 checklistsDec 8-14: 8.0% of 4920 checklistsDec 15-21: 5.2% of 6416 checklistsDec 22-31: 6.6% of 7659 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 New Hampshire 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 New Hampshire

Best counties

Share of checklists at the peak
  1. Strafford CountyBest early September · 572 checklists that week, 41,888 in all24%
  2. Rockingham CountyBest the second week of September · 1271 checklists that week, 84,864 in all24%
  3. Hillsborough CountyBest mid January · 813 checklists that week, 50,125 in all4.2%
  4. Coos CountyBest late March · 570 checklists that week, 27,719 in all2.6%
  5. Belknap CountyBest early December · 138 checklists that week, 13,295 in all1.5%
  6. Cheshire CountyBest early March · 667 checklists that week, 39,834 in all0.6%

Best spots

Share of checklists at the peak
  1. Gosport HarborRockingham County, best mid June · 20 checklists that week, 583 in all99%
  2. Hampton HarborRockingham County, best late August · 54 checklists that week, 611 in all97%
  3. Cocheco River ReservoirStrafford County, best early November · 56 checklists that week, 2,281 in all95%
  4. Pickering Ponds Recreation AreaStrafford County, best mid November · 46 checklists that week, 5,064 in all88%
  5. Hampton Beach State ParkRockingham County, best late June · 31 checklists that week, 2,502 in all72%
  6. Odiornes PointRockingham County, best the second week of July · 46 checklists that week, 5,375 in all69%

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

Best time of day

In New Hampshire, the Great Black-backed Gull is most often listed on checklists started between 10 am and 12 pm (6.3% of those checklists).

0%2%4%6%8%12 am: too few checklists (219) to judge1 am: too few checklists (192) to judge2 am: too few checklists (176) to judge3 am: too few checklists (234) to judge4 am: too few checklists (1042) to judge5 am: too few checklists (6352) to judge6 am: 4.5% of 23140 checklists7 am: 4.4% of 43401 checklists8 am: 6.3% of 48039 checklists9 am: 5.8% of 43328 checklists10 am: 6.4% of 37073 checklists11 am: 6.3% of 32028 checklists12 pm: 5.7% of 27396 checklists1 pm: 6.1% of 25182 checklists2 pm: 5.4% of 24318 checklists3 pm: 4.5% of 21974 checklists4 pm: 3.2% of 17958 checklists5 pm: 2.5% of 14528 checklists6 pm: 2.3% of 9144 checklists7 pm: too few checklists (5341) to judge8 pm: too few checklists (1845) to judge9 pm: too few checklists (578) to judge10 pm: too few checklists (346) to judge11 pm: too few checklists (256) 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
January8.1%7.0%6.2%6.3%
February5.3%4.6%4.0%5.0%
March5.1%4.5%3.9%4.0%
April3.4%3.2%2.7%3.1%
May3.1%3.0%3.5%3.8%
June3.5%2.7%3.0%3.3%
July3.1%5.3%4.9%5.3%
August6.8%6.8%7.4%7.5%
September7.2%7.6%7.1%6.6%
October5.7%6.2%7.0%8.0%
November8.0%7.2%6.7%8.2%
December7.7%8.0%5.2%6.6%

Neighboring states

  • Massachusetts: year-round, peaks the second week of August
  • Vermont: arrives late July, in the same week than New Hampshire
  • Rhode Island: arrives mid June, 5 weeks earlier than New Hampshire
  • Maine: arrives the second week of July, 2 weeks earlier than New Hampshire

Common questions

When do Great Black-backed Gulls arrive in New Hampshire?
Great Black-backed Gulls are in New Hampshire all year, but most are here in fall: numbers build from late July, peak in early December (8.0% of checklists), and fall back by late January. In the quietest week (mid June) they are still on about 3.0% of checklists.
When do Great Black-backed Gulls leave New Hampshire?
Great Black-backed Gulls never fully leave New Hampshire: numbers fall back below half their usual rate by late January, but some are still reported in every week, about 3.0% of checklists at the low.
When is the best time to see a Great Black-backed Gull in New Hampshire?
The Great Black-backed Gull is reported most often in early December, on about 8.0% of New Hampshire checklists.
Where in New Hampshire are Great Black-backed Gulls seen most often?
By county, Strafford County, Rockingham County, and Hillsborough County have the highest peak reporting rates for the Great Black-backed Gull (counties with at least 200 checklists).