WhenToBird

Chroicocephalus philadelphia · Laridae

When Do Bonaparte's Gulls Arrive in Washington?

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

Bonaparte's Gulls are winter birds in Washington: they arrive in mid July, peak in early November (6.0% of checklists), and most are gone by early January.

When to look

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

Best: early November. First arrivals mid July; most are gone by early January. Peak: on about 6.0% of Washington checklists.

  1. Januncommon
  2. Febrare
  3. Marrare
  4. Apruncommon
  5. Mayuncommon
  6. Junrare
  7. Juluncommon
  8. Auguncommon
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%2%4%6%8%Jan 1-7: 1.1% of 41928 checklistsJan 8-14: 1.1% of 31152 checklistsJan 15-21: 0.9% of 31753 checklistsJan 22-31: 0.8% of 42530 checklistsFeb 1-7: 0.7% of 29739 checklistsFeb 8-14: 0.5% of 32746 checklistsFeb 15-21: 0.4% of 40328 checklistsFeb 22-28: 0.5% of 28432 checklistsMar 1-7: 0.3% of 30758 checklistsMar 8-14: 0.4% of 29368 checklistsMar 15-21: 0.4% of 32580 checklistsMar 22-31: 0.5% of 45614 checklistsApr 1-7: 1.2% of 33997 checklistsApr 8-14: 1.3% of 34729 checklistsApr 15-21: 2.4% of 38474 checklistsApr 22-30: 2.3% of 52185 checklistsMay 1-7: 1.4% of 44236 checklistsMay 8-14: 1.0% of 48708 checklistsMay 15-21: 1.0% of 41742 checklistsMay 22-31: 0.9% of 57082 checklistsJun 1-7: 0.6% of 39193 checklistsJun 8-14: 0.4% of 36042 checklistsJun 15-21: 0.5% of 34003 checklistsJun 22-30: 0.5% of 39711 checklistsJul 1-7: 0.5% of 31949 checklistsJul 8-14: 0.9% of 29086 checklistsJul 15-21: 1.2% of 28045 checklistsJul 22-31: 1.6% of 38275 checklistsAug 1-7: 2.0% of 28846 checklistsAug 8-14: 2.2% of 28036 checklistsAug 15-21: 2.3% of 27614 checklistsAug 22-31: 2.0% of 40356 checklistsSep 1-7: 1.7% of 31214 checklistsSep 8-14: 2.4% of 27795 checklistsSep 15-21: 2.4% of 29677 checklistsSep 22-30: 2.4% of 35241 checklistsOct 1-7: 2.6% of 28605 checklistsOct 8-14: 3.5% of 28655 checklistsOct 15-21: 5.1% of 24643 checklistsOct 22-31: 6.0% of 34874 checklistsNov 1-7: 6.2% of 25658 checklistsNov 8-14: 5.9% of 25700 checklistsNov 15-21: 4.7% of 24331 checklistsNov 22-30: 3.6% of 32784 checklistsDec 1-7: 2.5% of 24099 checklistsDec 8-14: 1.6% of 23339 checklistsDec 15-21: 1.4% of 27666 checklistsDec 22-31: 1.3% of 42130 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 Washington 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 Washington

Best counties

Share of checklists at the peak
  1. Kitsap CountyBest late October · 1640 checklists that week, 74,545 in all16%
  2. Pierce CountyBest late October · 1817 checklists that week, 92,224 in all15%
  3. Columbia CountyBest early November · 21 checklists that week, 1,894 in all14%
  4. Jefferson CountyBest the second week of November · 912 checklists that week, 59,663 in all13%
  5. Snohomish CountyBest the second week of November · 2062 checklists that week, 131,467 in all11%
  6. Mason CountyBest the second week of November · 545 checklists that week, 27,853 in all11%

Best spots

Share of checklists at the peak
  1. Cottonwood BeachWhatcom County, best mid September · 44 checklists that week, 473 in all91%
  2. Point Defiance Park (northwest)Pierce County, best late October · 22 checklists that week, 446 in all87%
  3. Point No PointKitsap County, best the second week of October · 98 checklists that week, 4,564 in all84%
  4. Marysville Sewage LagoonSnohomish County, best the second week of October · 33 checklists that week, 1,523 in all83%
  5. Dumas BayKing County, best the second week of April · 38 checklists that week, 449 in all80%
  6. Norwegian Point ParkKitsap County, best mid September · 29 checklists that week, 723 in all79%

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

Best time of day

In Washington, the Bonaparte's Gull is most often listed on checklists started between 6 and 8 am (2.0% of those checklists).

0%0.5%1%1.5%2%12 am: too few checklists (796) to judge1 am: too few checklists (776) to judge2 am: too few checklists (709) to judge3 am: too few checklists (901) to judge4 am: too few checklists (3221) to judge5 am: too few checklists (16576) to judge6 am: 2.0% of 56744 checklists7 am: 2.0% of 133294 checklists8 am: 1.7% of 184196 checklists9 am: 1.8% of 186303 checklists10 am: 1.9% of 177063 checklists11 am: 1.8% of 154936 checklists12 pm: 1.8% of 138061 checklists1 pm: 1.8% of 127449 checklists2 pm: 1.8% of 121511 checklists3 pm: 1.6% of 107793 checklists4 pm: 1.3% of 82862 checklists5 pm: 1.1% of 57183 checklists6 pm: 0.8% of 39886 checklists7 pm: too few checklists (26969) to judge8 pm: too few checklists (12427) to judge9 pm: too few checklists (3658) to judge10 pm: too few checklists (1500) to judge11 pm: too few checklists (834) 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
January1.1%1.1%0.9%0.8%
February0.7%0.5%0.4%0.5%
March0.3%0.4%0.4%0.5%
April1.2%1.3%2.4%2.3%
May1.4%1.0%1.0%0.9%
June0.6%0.4%0.5%0.5%
July0.5%0.9%1.2%1.6%
August2.0%2.2%2.3%2.0%
September1.7%2.4%2.4%2.4%
October2.6%3.5%5.1%6.0%
November6.2%5.9%4.7%3.6%
December2.5%1.6%1.4%1.3%

Neighboring states

  • Oregon: arrives the second week of July, 1 week earlier than Washington
  • Idaho: arrives early August, 2 weeks later than Washington
  • Montana: arrives late July, 1 week later than Washington
  • Nevada: arrives early July, 2 weeks earlier than Washington

Common questions

When do Bonaparte's Gulls arrive in Washington?
Bonaparte's Gulls are winter birds in Washington: they arrive in mid July, peak in early November (6.0% of checklists), and most are gone by early January.
When do Bonaparte's Gulls leave Washington?
Most Bonaparte's Gulls have left Washington by early January, when reports fall below half their usual rate. Stragglers are still reported until the second week of January.
When is the best time to see a Bonaparte's Gull in Washington?
The Bonaparte's Gull is reported most often in early November, on about 6.0% of Washington checklists.
Where in Washington are Bonaparte's Gulls seen most often?
By county, Kitsap County, Pierce County, and Columbia County have the highest peak reporting rates for the Bonaparte's Gull (counties with at least 200 checklists).