WhenToBird

Larus occidentalis · Laridae

When Do Western Gulls Arrive in California?

Adult Western Gull
Photo: emilyd47, CC BY-SA 4.0 via iNaturalist

The Western Gull is in California all year. It turns up on about 23% of checklists at its peak (mid August) and on 13% in its quietest week (mid April).

When to look

PresentAll year
Peak weekAug 15-21mid August
Quietest weekApr 15-21mid April

Best: mid August. Here all year. Peak: on about 23% of California checklists.

  1. Janpeak season
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Julpeak season
  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%10%20%30%Jan 1-7: 19% of 112336 checklistsJan 8-14: 19% of 85518 checklistsJan 15-21: 18% of 86488 checklistsJan 22-31: 17% of 116174 checklistsFeb 1-7: 17% of 75171 checklistsFeb 8-14: 15% of 84467 checklistsFeb 15-21: 14% of 105683 checklistsFeb 22-28: 17% of 83396 checklistsMar 1-7: 17% of 77470 checklistsMar 8-14: 15% of 75180 checklistsMar 15-21: 15% of 80770 checklistsMar 22-31: 14% of 114116 checklistsApr 1-7: 13% of 84057 checklistsApr 8-14: 13% of 83692 checklistsApr 15-21: 13% of 89242 checklistsApr 22-30: 13% of 114289 checklistsMay 1-7: 14% of 85728 checklistsMay 8-14: 14% of 91984 checklistsMay 15-21: 14% of 75478 checklistsMay 22-31: 13% of 106250 checklistsJun 1-7: 13% of 70051 checklistsJun 8-14: 14% of 67485 checklistsJun 15-21: 14% of 66269 checklistsJun 22-30: 15% of 79172 checklistsJul 1-7: 16% of 62877 checklistsJul 8-14: 18% of 60328 checklistsJul 15-21: 19% of 59705 checklistsJul 22-31: 21% of 83796 checklistsAug 1-7: 22% of 60215 checklistsAug 8-14: 22% of 60172 checklistsAug 15-21: 23% of 59877 checklistsAug 22-31: 23% of 89107 checklistsSep 1-7: 22% of 72000 checklistsSep 8-14: 21% of 71228 checklistsSep 15-21: 19% of 76808 checklistsSep 22-30: 18% of 100204 checklistsOct 1-7: 18% of 76571 checklistsOct 8-14: 17% of 80874 checklistsOct 15-21: 17% of 74581 checklistsOct 22-31: 18% of 97498 checklistsNov 1-7: 19% of 70851 checklistsNov 8-14: 20% of 72431 checklistsNov 15-21: 20% of 66767 checklistsNov 22-30: 20% of 94737 checklistsDec 1-7: 20% of 65393 checklistsDec 8-14: 19% of 67449 checklistsDec 15-21: 16% of 83421 checklistsDec 22-31: 19% of 124993 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 California 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 California

Best counties

Share of checklists at the peak
  1. Monterey CountyBest early December · 2617 checklists that week, 132,505 in all60%
  2. San Francisco CountyBest late July · 2962 checklists that week, 130,018 in all56%
  3. Del Norte CountyBest early September · 426 checklists that week, 16,363 in all50%
  4. San Luis Obispo CountyBest the second week of August · 2076 checklists that week, 124,667 in all46%
  5. Humboldt CountyBest the second week of August · 1460 checklists that week, 95,963 in all42%
  6. Ventura CountyBest the second week of August · 1473 checklists that week, 94,391 in all40%

Best spots

Share of checklists at the peak
  1. San Francisco ZooSan Francisco County, best early September · 21 checklists that week, 883 in all100%
  2. Salt Pond (historical)Los Angeles County, best late March · 22 checklists that week, 776 in all100%
  3. Point San PabloContra Costa County, best early August · 21 checklists that week, 455 in all100%
  4. Alcatraz IslandSan Francisco County, best mid June · 24 checklists that week, 721 in all100%
  5. Ocean BeachSan Francisco County, best mid September · 22 checklists that week, 1,391 in all100%

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

Best time of day

In California, the Western Gull is most often listed on checklists started between 1 and 3 pm (19% of those checklists).

0%5%10%15%20%12 am: too few checklists (1688) to judge1 am: too few checklists (1451) to judge2 am: too few checklists (1402) to judge3 am: too few checklists (1743) to judge4 am: too few checklists (4647) to judge5 am: too few checklists (32158) to judge6 am: 17% of 186053 checklists7 am: 17% of 444086 checklists8 am: 17% of 535846 checklists9 am: 17% of 486061 checklists10 am: 17% of 411130 checklists11 am: 18% of 325798 checklists12 pm: 18% of 269132 checklists1 pm: 19% of 244762 checklists2 pm: 19% of 235420 checklists3 pm: 18% of 232365 checklists4 pm: 17% of 208688 checklists5 pm: 16% of 146104 checklists6 pm: 14% of 96867 checklists7 pm: too few checklists (50942) to judge8 pm: too few checklists (14803) to judge9 pm: too few checklists (5561) to judge10 pm: too few checklists (3546) to judge11 pm: too few checklists (2092) 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
January19%19%18%17%
February17%15%14%17%
March17%15%15%14%
April13%13%13%13%
May14%14%14%13%
June13%14%14%15%
July16%18%19%21%
August22%22%23%23%
September22%21%19%18%
October18%17%17%18%
November19%20%20%20%
December20%19%16%19%

Neighboring states

  • Oregon: year-round, peaks early September
  • Washington: summer visitor, peaks mid September

Common questions

When do Western Gulls arrive in California?
The Western Gull is in California all year. It turns up on about 23% of checklists at its peak (mid August) and on 13% in its quietest week (mid April).
When do Western Gulls leave California?
The Western Gull does not leave California: it is reported all year, from 13% of checklists in mid April to 23% in mid August.
When is the best time to see a Western Gull in California?
The Western Gull is reported most often in mid August, on about 23% of California checklists.
Where in California are Western Gulls seen most often?
By county, Monterey County, San Francisco County, and Del Norte County have the highest peak reporting rates for the Western Gull (counties with at least 200 checklists).