WhenToBird

Larus heermanni · Laridae

When Do Heermann's Gulls Arrive in Washington?

Adult Heermann's Gull
Photo: Ken Clark, CC BY 4.0 via iNaturalist

Heermann's Gulls reach Washington in early July, are common by mid July, peak in mid September (6.3% of checklists), and most are gone by the second week of November.

When to look

First arrivalsJul 1-7early July
Common byJul 15-21mid July
PeakSep 15-21mid September
Most gone byNov 8-14the second week of November

Best: mid September. First arrivals early July; most are gone by the second week of November. Peak: on about 6.3% of Washington checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Maynot usually seen
  6. Jununcommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Decrare

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

0%2%4%6%8%Jan 1-7: 0.1% of 41928 checklistsJan 8-14: 0.1% of 31152 checklistsJan 15-21: 0.1% of 31753 checklistsJan 22-31: 0% of 42530 checklistsFeb 1-7: 0.1% of 29739 checklistsFeb 8-14: 0% of 32746 checklistsFeb 15-21: 0% of 40328 checklistsFeb 22-28: 0% of 28432 checklistsMar 1-7: 0% of 30758 checklistsMar 8-14: 0.1% of 29368 checklistsMar 15-21: 0.1% of 32580 checklistsMar 22-31: 0% of 45614 checklistsApr 1-7: 0.1% of 33997 checklistsApr 8-14: 0% of 34729 checklistsApr 15-21: 0.1% of 38474 checklistsApr 22-30: 0.1% of 52185 checklistsMay 1-7: 0.1% of 44236 checklistsMay 8-14: 0.1% of 48708 checklistsMay 15-21: 0.1% of 41742 checklistsMay 22-31: 0.1% of 57082 checklistsJun 1-7: 0.2% of 39193 checklistsJun 8-14: 0.3% of 36042 checklistsJun 15-21: 0.6% of 34003 checklistsJun 22-30: 1.0% of 39711 checklistsJul 1-7: 1.4% of 31949 checklistsJul 8-14: 2.5% of 29086 checklistsJul 15-21: 3.2% of 28045 checklistsJul 22-31: 4.5% of 38275 checklistsAug 1-7: 4.9% of 28846 checklistsAug 8-14: 5.2% of 28036 checklistsAug 15-21: 5.1% of 27614 checklistsAug 22-31: 5.4% of 40356 checklistsSep 1-7: 5.7% of 31214 checklistsSep 8-14: 6.7% of 27795 checklistsSep 15-21: 6.3% of 29677 checklistsSep 22-30: 5.9% of 35241 checklistsOct 1-7: 5.4% of 28605 checklistsOct 8-14: 6.1% of 28655 checklistsOct 15-21: 6.2% of 24643 checklistsOct 22-31: 5.1% of 34874 checklistsNov 1-7: 3.2% of 25658 checklistsNov 8-14: 2.2% of 25700 checklistsNov 15-21: 2.1% of 24331 checklistsNov 22-30: 1.2% of 32784 checklistsDec 1-7: 0.6% of 24099 checklistsDec 8-14: 0.3% of 23339 checklistsDec 15-21: 0.1% of 27666 checklistsDec 22-31: 0.1% 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. Pacific CountyBest early September · 467 checklists that week, 19,516 in all31%
  2. Grays Harbor CountyBest mid August · 907 checklists that week, 28,443 in all26%
  3. Jefferson CountyBest the second week of October · 891 checklists that week, 59,663 in all25%
  4. Clallam CountyBest early October · 1726 checklists that week, 85,362 in all17%
  5. San Juan CountyBest early September · 869 checklists that week, 35,337 in all16%
  6. Snohomish CountyBest mid October · 2049 checklists that week, 131,467 in all14%

Best spots

Share of checklists at the peak
  1. San Juan Islands National Wildlife RefugeIsland County, best mid August · 24 checklists that week, 403 in all97%
  2. Fort Worden (Point Wilson)Jefferson County, best early August · 117 checklists that week, 947 in all96%
  3. Point HudsonJefferson County, best early October · 26 checklists that week, 1,620 in all90%
  4. Commodore ParkKing County, best early November · 28 checklists that week, 404 in all90%
  5. Point WilsonJefferson County, best late July · 45 checklists that week, 1,948 in all89%

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

Best time of day

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

0%1%2%3%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: 2.1% of 56744 checklists7 am: 2.0% of 133294 checklists8 am: 1.6% of 184196 checklists9 am: 1.7% of 186303 checklists10 am: 1.7% of 177063 checklists11 am: 1.7% of 154936 checklists12 pm: 1.6% of 138061 checklists1 pm: 1.7% of 127449 checklists2 pm: 1.7% of 121511 checklists3 pm: 1.8% of 107793 checklists4 pm: 1.9% of 82862 checklists5 pm: 1.9% of 57183 checklists6 pm: 1.5% 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
January0.1%0.1%0.1%0%
February0.1%0%0%0%
March0%0.1%0.1%0%
April0.1%0%0.1%0.1%
May0.1%0.1%0.1%0.1%
June0.2%0.3%0.6%1.0%
July1.4%2.5%3.2%4.5%
August4.9%5.2%5.1%5.4%
September5.7%6.7%6.3%5.9%
October5.4%6.1%6.2%5.1%
November3.2%2.2%2.1%1.2%
December0.6%0.3%0.1%0.1%

Neighboring states

  • Oregon: arrives early July, in the same week than Washington
  • California: arrives late May, 5 weeks earlier than Washington

Common questions

When do Heermann's Gulls arrive in Washington?
Heermann's Gulls reach Washington in early July, are common by mid July, peak in mid September (6.3% of checklists), and most are gone by the second week of November.
When do Heermann's Gulls leave Washington?
Most Heermann's Gulls have left Washington by the second week of November, when reports fall below half their usual rate. Stragglers are still reported until late November.
When is the best time to see a Heermann's Gull in Washington?
The Heermann's Gull is reported most often in mid September, on about 6.3% of Washington checklists.
Where in Washington are Heermann's Gulls seen most often?
By county, Pacific County, Grays Harbor County, and Jefferson County have the highest peak reporting rates for the Heermann's Gull (counties with at least 200 checklists).