WhenToBird

Chroicocephalus philadelphia · Laridae

When Do Bonaparte's Gulls Arrive in Vermont?

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

Bonaparte's Gulls are winter birds in Vermont: they arrive in mid July, peak in early November (2.9% of checklists), and most are gone by early December.

When to look

First arrivalsJul 15-21mid July
Common byJul 15-21mid July
PeakNov 1-7early November
Most gone byDec 1-7early December

Best: early November. First arrivals mid July; most are gone by early December. Peak: on about 2.9% of Vermont checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Apruncommon
  5. Mayuncommon
  6. Junnot usually seen
  7. Juluncommon
  8. Augcommon
  9. Sepuncommon
  10. Octpeak season
  11. Novpeak season
  12. Decrare

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

0%1%2%3%4%Jan 1-7: 0.1% of 12234 checklistsJan 8-14: 0% of 8293 checklistsJan 15-21: 0.1% of 7885 checklistsJan 22-31: 0% of 10534 checklistsFeb 1-7: 0.1% of 7212 checklistsFeb 8-14: 0% of 8144 checklistsFeb 15-21: 0% of 10480 checklistsFeb 22-28: 0% of 7932 checklistsMar 1-7: 0% of 8192 checklistsMar 8-14: 0% of 9383 checklistsMar 15-21: 0% of 10620 checklistsMar 22-31: 0.1% of 16257 checklistsApr 1-7: 0.3% of 12568 checklistsApr 8-14: 0.3% of 14677 checklistsApr 15-21: 0.4% of 14106 checklistsApr 22-30: 0.7% of 19617 checklistsMay 1-7: 1.1% of 18143 checklistsMay 8-14: 0.5% of 19626 checklistsMay 15-21: 0.1% of 17779 checklistsMay 22-31: 0.2% of 20310 checklistsJun 1-7: 0.1% of 11493 checklistsJun 8-14: 0.1% of 10215 checklistsJun 15-21: 0.1% of 9951 checklistsJun 22-30: 0.1% of 11050 checklistsJul 1-7: 0.1% of 8690 checklistsJul 8-14: 0.1% of 7679 checklistsJul 15-21: 0.1% of 7687 checklistsJul 22-31: 0.8% of 10712 checklistsAug 1-7: 1.0% of 7703 checklistsAug 8-14: 1.5% of 7743 checklistsAug 15-21: 1.3% of 8314 checklistsAug 22-31: 0.5% of 12428 checklistsSep 1-7: 0.5% of 9526 checklistsSep 8-14: 0.5% of 8493 checklistsSep 15-21: 0.6% of 8283 checklistsSep 22-30: 0.7% of 10352 checklistsOct 1-7: 0.7% of 8802 checklistsOct 8-14: 1.0% of 9088 checklistsOct 15-21: 1.7% of 7739 checklistsOct 22-31: 2.9% of 10907 checklistsNov 1-7: 3.9% of 7868 checklistsNov 8-14: 1.7% of 7223 checklistsNov 15-21: 1.1% of 7224 checklistsNov 22-30: 0.6% of 8375 checklistsDec 1-7: 0.4% of 6580 checklistsDec 8-14: 0.1% of 6800 checklistsDec 15-21: 0.1% of 8334 checklistsDec 22-31: 0.2% of 10579 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 Vermont 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 Vermont

Best counties

Share of checklists at the peak
  1. Grand Isle CountyBest late October · 234 checklists that week, 8,507 in all26%
  2. Franklin CountyBest late October · 386 checklists that week, 25,284 in all10%
  3. Chittenden CountyBest early November · 1770 checklists that week, 109,477 in all6.9%
  4. Addison CountyBest early November · 1540 checklists that week, 77,064 in all2.8%
  5. Windham CountyBest late April · 1728 checklists that week, 39,105 in all1.7%
  6. Lamoille CountyBest early May · 574 checklists that week, 16,426 in all1.3%

Best spots

Share of checklists at the peak
  1. Holmes CreekChittenden County, best the second week of August · 41 checklists that week, 2,478 in all68%
  2. Chimney PointAddison County, best the second week of May · 31 checklists that week, 1,924 in all52%
  3. Goose BayFranklin County, best the second week of October · 22 checklists that week, 213 in all50%
  4. Town Farm BayChittenden County, best early November · 35 checklists that week, 361 in all48%
  5. La Platte RiverChittenden County, best early November · 187 checklists that week, 4,615 in all46%
  6. St. Albans Town BeachFranklin County, best mid October · 22 checklists that week, 539 in all34%

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

Best time of day

In Vermont, the Bonaparte's Gull is most often listed on checklists started between 11 am and 1 pm (0.6% of those checklists).

0%0.5%1%12 am: too few checklists (384) to judge1 am: too few checklists (418) to judge2 am: too few checklists (568) to judge3 am: too few checklists (1183) to judge4 am: too few checklists (3460) to judge5 am: 0.6% of 10340 checklists6 am: 0.6% of 30951 checklists7 am: 0.5% of 64150 checklists8 am: 0.4% of 70252 checklists9 am: 0.5% of 55280 checklists10 am: 0.6% of 47111 checklists11 am: 0.7% of 37615 checklists12 pm: 0.6% of 32195 checklists1 pm: 0.6% of 30185 checklists2 pm: 0.6% of 29679 checklists3 pm: 0.6% of 26483 checklists4 pm: 0.7% of 20110 checklists5 pm: 0.5% of 15993 checklists6 pm: 0.3% of 12110 checklists7 pm: too few checklists (8203) to judge8 pm: too few checklists (4425) to judge9 pm: too few checklists (1829) to judge10 pm: too few checklists (597) to judge11 pm: too few checklists (309) 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
January0.1%0%0.1%0%
February0.1%0%0%0%
March0%0%0%0.1%
April0.3%0.3%0.4%0.7%
May1.1%0.5%0.1%0.2%
June0.1%0.1%0.1%0.1%
July0.1%0.1%0.1%0.8%
August1.0%1.5%1.3%0.5%
September0.5%0.5%0.6%0.7%
October0.7%1.0%1.7%2.9%
November3.9%1.7%1.1%0.6%
December0.4%0.1%0.1%0.2%

Neighboring states

  • New Hampshire: arrives the second week of July, 1 week earlier than Vermont
  • Massachusetts: arrives mid June, 4 weeks earlier than Vermont
  • Connecticut: arrives late July, 1 week later than Vermont
  • Rhode Island: arrives the second week of October, 11 weeks later than Vermont

Common questions

When do Bonaparte's Gulls arrive in Vermont?
Bonaparte's Gulls are winter birds in Vermont: they arrive in mid July, peak in early November (2.9% of checklists), and most are gone by early December.
When do Bonaparte's Gulls leave Vermont?
Most Bonaparte's Gulls have left Vermont by early December, when reports fall below half their usual rate.
When is the best time to see a Bonaparte's Gull in Vermont?
The Bonaparte's Gull is reported most often in early November, on about 2.9% of Vermont checklists.
Where in Vermont are Bonaparte's Gulls seen most often?
By county, Grand Isle County, Franklin County, and Chittenden County have the highest peak reporting rates for the Bonaparte's Gull (counties with at least 200 checklists).