WhenToBird

Chroicocephalus philadelphia · Laridae

When Do Bonaparte's Gulls Arrive in New Hampshire?

Adult Bonaparte's Gull
Photo: Kevin Krebs, CC BY 4.0 via iNaturalist

Bonaparte's Gulls arrive in New Hampshire in the second week of July, peak in the second week of August (1.6% of checklists), and most are gone by early January.

When to look

First arrivalsJul 8-14the second week of July
Common byJul 8-14the second week of July
PeakAug 8-14the second week of August
Most gone byJan 1-7early January

Best: the second week of August. First arrivals the second week of July; most are gone by early January. Peak: on about 1.6% of New Hampshire checklists.

  1. Januncommon
  2. Febnot usually seen
  3. Marrare
  4. Apruncommon
  5. Mayuncommon
  6. Jununcommon
  7. Julcommon
  8. Augpeak season
  9. Sepcommon
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%0.5%1%1.5%2%Jan 1-7: 0.5% of 8253 checklistsJan 8-14: 0.1% of 5998 checklistsJan 15-21: 0.1% of 5734 checklistsJan 22-31: 0.1% of 7776 checklistsFeb 1-7: 0.1% of 5253 checklistsFeb 8-14: 0% of 6802 checklistsFeb 15-21: 0% of 8852 checklistsFeb 22-28: 0% of 5792 checklistsMar 1-7: 0.1% of 6187 checklistsMar 8-14: 0.1% of 6977 checklistsMar 15-21: 0.1% of 7863 checklistsMar 22-31: 0.1% of 11746 checklistsApr 1-7: 0.3% of 9329 checklistsApr 8-14: 0.2% of 10499 checklistsApr 15-21: 0.3% of 10376 checklistsApr 22-30: 0.4% of 13086 checklistsMay 1-7: 0.6% of 13198 checklistsMay 8-14: 0.2% of 14980 checklistsMay 15-21: 0.4% of 12487 checklistsMay 22-31: 0.7% of 14294 checklistsJun 1-7: 0.4% of 8974 checklistsJun 8-14: 0.3% of 8395 checklistsJun 15-21: 0.1% of 7670 checklistsJun 22-30: 0.1% of 9188 checklistsJul 1-7: 0.1% of 7707 checklistsJul 8-14: 0.4% of 6554 checklistsJul 15-21: 0.6% of 6636 checklistsJul 22-31: 0.8% of 9599 checklistsAug 1-7: 1.6% of 6436 checklistsAug 8-14: 1.5% of 6477 checklistsAug 15-21: 1.6% of 6510 checklistsAug 22-31: 1.1% of 9762 checklistsSep 1-7: 1.1% of 6700 checklistsSep 8-14: 0.9% of 6012 checklistsSep 15-21: 1.0% of 6238 checklistsSep 22-30: 0.8% of 7619 checklistsOct 1-7: 0.7% of 6702 checklistsOct 8-14: 1.2% of 6863 checklistsOct 15-21: 1.7% of 6284 checklistsOct 22-31: 1.2% of 8287 checklistsNov 1-7: 1.2% of 7584 checklistsNov 8-14: 0.9% of 6056 checklistsNov 15-21: 0.6% of 5597 checklistsNov 22-30: 0.8% of 7140 checklistsDec 1-7: 0.8% of 4623 checklistsDec 8-14: 0.5% of 4920 checklistsDec 15-21: 0.5% of 6416 checklistsDec 22-31: 0.7% 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. Rockingham CountyBest the second week of August · 1325 checklists that week, 84,864 in all6.8%
  2. Sullivan CountyBest late April · 373 checklists that week, 13,105 in all1.2%
  3. Cheshire CountyBest late April · 1337 checklists that week, 39,834 in all1.1%
  4. Coos CountyBest early May · 724 checklists that week, 27,719 in all0.8%
  5. Grafton CountyBest late April · 1785 checklists that week, 45,699 in all0.6%
  6. Belknap CountyBest late April · 440 checklists that week, 13,295 in all0.6%

Best spots

Share of checklists at the peak
  1. Odiornes PointRockingham County, best the second week of August · 85 checklists that week, 5,375 in all37%
  2. Little Harbor (Sheafes Point)Rockingham County, best late December · 24 checklists that week, 108 in all29%
  3. Odiornes Point (High Rock)Rockingham County, best early August · 40 checklists that week, 869 in all23%
  4. Ragged Neck PointRockingham County, best mid August · 33 checklists that week, 2,179 in all19%
  5. Hampton HarborRockingham County, best the second week of August · 25 checklists that week, 611 in all14%

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

Best time of day

In New Hampshire, the Bonaparte's Gull is most often listed on checklists started between 10 am and 12 pm (0.7% of those checklists).

0%0.5%1%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: 0.4% of 23140 checklists7 am: 0.4% of 43401 checklists8 am: 0.5% of 48039 checklists9 am: 0.5% of 43328 checklists10 am: 0.7% of 37073 checklists11 am: 0.7% of 32028 checklists12 pm: 0.7% of 27396 checklists1 pm: 0.6% of 25182 checklists2 pm: 0.6% of 24318 checklists3 pm: 0.5% of 21974 checklists4 pm: 0.4% of 17958 checklists5 pm: 0.5% of 14528 checklists6 pm: 0.4% 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
January0.5%0.1%0.1%0.1%
February0.1%0%0%0%
March0.1%0.1%0.1%0.1%
April0.3%0.2%0.3%0.4%
May0.6%0.2%0.4%0.7%
June0.4%0.3%0.1%0.1%
July0.1%0.4%0.6%0.8%
August1.6%1.5%1.6%1.1%
September1.1%0.9%1.0%0.8%
October0.7%1.2%1.7%1.2%
November1.2%0.9%0.6%0.8%
December0.8%0.5%0.5%0.7%

Neighboring states

  • Massachusetts: arrives mid June, 3 weeks earlier than New Hampshire
  • Vermont: arrives mid July, 1 week later than New Hampshire
  • Rhode Island: arrives the second week of October, 12 weeks later than New Hampshire
  • Maine: arrives early June, 5 weeks earlier than New Hampshire

Common questions

When do Bonaparte's Gulls arrive in New Hampshire?
Bonaparte's Gulls arrive in New Hampshire in the second week of July, peak in the second week of August (1.6% of checklists), and most are gone by early January.
When do Bonaparte's Gulls leave New Hampshire?
Most Bonaparte's Gulls have left New Hampshire by early January, when reports fall below half their usual rate.
When is the best time to see a Bonaparte's Gull in New Hampshire?
The Bonaparte's Gull is reported most often in the second week of August, on about 1.6% of New Hampshire checklists.
Where in New Hampshire are Bonaparte's Gulls seen most often?
By county, Rockingham County, Sullivan County, and Cheshire County have the highest peak reporting rates for the Bonaparte's Gull (counties with at least 200 checklists).