WhenToBird

Aechmophorus occidentalis · Podicipedidae

When Do Western Grebes Arrive in California?

Adult Western Grebe
Photo: Craig K, CC BY 4.0 via iNaturalist

Western Grebes are in California all year, but most are here in winter: numbers build from late October, peak in early January (8.0% of checklists), and fall back by early April. In the quietest week (the second week of September) they are still on about 3.0% of checklists.

When to look

Numbers buildOct 22-31late October
PeakJan 1-7early January
Fall back byApr 1-7early April
FewestSep 8-14the second week of September

Best: early January. Here all year; numbers build from late October and fall back by early April. Peak: on about 8.0% of California checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Maycommon
  6. Juncommon
  7. Juluncommon
  8. Augcommon
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Decpeak season

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

0%5%10%Jan 1-7: 8.0% of 112336 checklistsJan 8-14: 7.9% of 85518 checklistsJan 15-21: 7.9% of 86488 checklistsJan 22-31: 7.7% of 116174 checklistsFeb 1-7: 7.2% of 75171 checklistsFeb 8-14: 6.9% of 84467 checklistsFeb 15-21: 6.1% of 105683 checklistsFeb 22-28: 7.4% of 83396 checklistsMar 1-7: 7.0% of 77470 checklistsMar 8-14: 6.7% of 75180 checklistsMar 15-21: 6.6% of 80770 checklistsMar 22-31: 5.9% of 114116 checklistsApr 1-7: 5.6% of 84057 checklistsApr 8-14: 5.0% of 83692 checklistsApr 15-21: 5.0% of 89242 checklistsApr 22-30: 4.5% of 114289 checklistsMay 1-7: 4.3% of 85728 checklistsMay 8-14: 3.8% of 91984 checklistsMay 15-21: 3.6% of 75478 checklistsMay 22-31: 3.4% of 106250 checklistsJun 1-7: 3.1% of 70051 checklistsJun 8-14: 3.2% of 67485 checklistsJun 15-21: 3.2% of 66269 checklistsJun 22-30: 3.3% of 79172 checklistsJul 1-7: 3.1% of 62877 checklistsJul 8-14: 3.0% of 60328 checklistsJul 15-21: 3.0% of 59705 checklistsJul 22-31: 3.1% of 83796 checklistsAug 1-7: 3.2% of 60215 checklistsAug 8-14: 3.2% of 60172 checklistsAug 15-21: 3.4% of 59877 checklistsAug 22-31: 3.1% of 89107 checklistsSep 1-7: 3.1% of 72000 checklistsSep 8-14: 3.0% of 71228 checklistsSep 15-21: 2.9% of 76808 checklistsSep 22-30: 3.2% of 100204 checklistsOct 1-7: 3.7% of 76571 checklistsOct 8-14: 4.5% of 80874 checklistsOct 15-21: 5.3% of 74581 checklistsOct 22-31: 6.3% of 97498 checklistsNov 1-7: 7.4% of 70851 checklistsNov 8-14: 7.6% of 72431 checklistsNov 15-21: 8.0% of 66767 checklistsNov 22-30: 8.2% of 94737 checklistsDec 1-7: 7.7% of 65393 checklistsDec 8-14: 7.7% of 67449 checklistsDec 15-21: 6.5% of 83421 checklistsDec 22-31: 8.0% 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. Lake CountyBest mid June · 179 checklists that week, 12,989 in all33%
  2. Imperial CountyBest late October · 425 checklists that week, 24,551 in all23%
  3. Del Norte CountyBest early November · 219 checklists that week, 16,363 in all20%
  4. San Francisco CountyBest late January · 3440 checklists that week, 130,018 in all18%
  5. Humboldt CountyBest the second week of March · 1452 checklists that week, 95,963 in all17%
  6. Lassen CountyBest mid October · 106 checklists that week, 8,378 in all16%

Best spots

Share of checklists at the peak
  1. Skinner ReservoirRiverside County, best late June · 21 checklists that week, 910 in all100%
  2. Calero ReservoirSanta Clara County, best the second week of May · 30 checklists that week, 998 in all96%
  3. Sweetwater ReservoirSan Diego County, best late November · 21 checklists that week, 755 in all95%
  4. Fletcher Retarding BasinOrange County, best late August · 28 checklists that week, 1,086 in all95%
  5. Frank G Bonelli Regional ParkLos Angeles County, best early June · 122 checklists that week, 7,491 in all94%

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

Best time of day

In California, the Western Grebe is most often listed on checklists started between 6 and 8 am (5.9% of those checklists).

0%2%4%6%8%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: 5.6% of 186053 checklists7 am: 6.1% of 444086 checklists8 am: 5.7% of 535846 checklists9 am: 5.7% of 486061 checklists10 am: 5.6% of 411130 checklists11 am: 5.6% of 325798 checklists12 pm: 5.6% of 269132 checklists1 pm: 5.7% of 244762 checklists2 pm: 5.7% of 235420 checklists3 pm: 5.4% of 232365 checklists4 pm: 4.5% of 208688 checklists5 pm: 3.6% of 146104 checklists6 pm: 2.8% 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
January8.0%7.9%7.9%7.7%
February7.2%6.9%6.1%7.4%
March7.0%6.7%6.6%5.9%
April5.6%5.0%5.0%4.5%
May4.3%3.8%3.6%3.4%
June3.1%3.2%3.2%3.3%
July3.1%3.0%3.0%3.1%
August3.2%3.2%3.4%3.1%
September3.1%3.0%2.9%3.2%
October3.7%4.5%5.3%6.3%
November7.4%7.6%8.0%8.2%
December7.7%7.7%6.5%8.0%

Neighboring states

  • Nevada: arrives late March, 20 weeks later than California
  • Utah: arrives mid March, 19 weeks later than California
  • Arizona: arrives the second week of September, 6 weeks earlier than California
  • Oregon: arrives late July, 12 weeks earlier than California

Common questions

When do Western Grebes arrive in California?
Western Grebes are in California all year, but most are here in winter: numbers build from late October, peak in early January (8.0% of checklists), and fall back by early April. In the quietest week (the second week of September) they are still on about 3.0% of checklists.
When do Western Grebes leave California?
Western Grebes never fully leave California: numbers fall back below half their usual rate by early April, but some are still reported in every week, about 3.0% of checklists at the low.
When is the best time to see a Western Grebe in California?
The Western Grebe is reported most often in early January, on about 8.0% of California checklists.
Where in California are Western Grebes seen most often?
By county, Lake County, Imperial County, and Del Norte County have the highest peak reporting rates for the Western Grebe (counties with at least 200 checklists).