WhenToBird

Pandion haliaetus · Pandionidae

When Do Ospreys Arrive in California?

Adult female Osprey
Photo: Bill Levine, CC BY 4.0 via iNaturalist

The Osprey is in California all year. It turns up on about 8.0% of checklists at its peak (the second week of August) and on 4.1% in its quietest week (the second week of February).

When to look

PresentAll year
Peak weekAug 8-14the second week of August
Quietest weekFeb 8-14the second week of February

Best: the second week of August. Here all year. Peak: on about 8.0% of California checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%5%10%Jan 1-7: 5.1% of 112336 checklistsJan 8-14: 4.9% of 85518 checklistsJan 15-21: 5.0% of 86488 checklistsJan 22-31: 4.5% of 116174 checklistsFeb 1-7: 4.3% of 75171 checklistsFeb 8-14: 4.1% of 84467 checklistsFeb 15-21: 4.0% of 105683 checklistsFeb 22-28: 4.9% of 83396 checklistsMar 1-7: 4.8% of 77470 checklistsMar 8-14: 5.0% of 75180 checklistsMar 15-21: 5.3% of 80770 checklistsMar 22-31: 5.2% of 114116 checklistsApr 1-7: 5.6% of 84057 checklistsApr 8-14: 5.2% of 83692 checklistsApr 15-21: 5.3% of 89242 checklistsApr 22-30: 5.3% of 114289 checklistsMay 1-7: 5.1% of 85728 checklistsMay 8-14: 5.1% of 91984 checklistsMay 15-21: 5.2% of 75478 checklistsMay 22-31: 5.4% of 106250 checklistsJun 1-7: 5.4% of 70051 checklistsJun 8-14: 5.9% of 67485 checklistsJun 15-21: 6.3% of 66269 checklistsJun 22-30: 6.3% of 79172 checklistsJul 1-7: 6.4% of 62877 checklistsJul 8-14: 6.7% of 60328 checklistsJul 15-21: 7.1% of 59705 checklistsJul 22-31: 7.4% of 83796 checklistsAug 1-7: 7.9% of 60215 checklistsAug 8-14: 8.1% of 60172 checklistsAug 15-21: 8.1% of 59877 checklistsAug 22-31: 7.8% of 89107 checklistsSep 1-7: 7.4% of 72000 checklistsSep 8-14: 6.5% of 71228 checklistsSep 15-21: 5.9% of 76808 checklistsSep 22-30: 5.3% of 100204 checklistsOct 1-7: 5.2% of 76571 checklistsOct 8-14: 5.3% of 80874 checklistsOct 15-21: 4.9% of 74581 checklistsOct 22-31: 5.1% of 97498 checklistsNov 1-7: 5.4% of 70851 checklistsNov 8-14: 5.3% of 72431 checklistsNov 15-21: 5.0% of 66767 checklistsNov 22-30: 5.3% of 94737 checklistsDec 1-7: 5.1% of 65393 checklistsDec 8-14: 5.0% of 67449 checklistsDec 15-21: 4.3% of 83421 checklistsDec 22-31: 5.0% 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 the second week of August · 223 checklists that week, 12,989 in all39%
  2. Del Norte CountyBest late April · 576 checklists that week, 16,363 in all28%
  3. Mono CountyBest mid August · 851 checklists that week, 38,666 in all24%
  4. Mendocino CountyBest mid August · 824 checklists that week, 47,934 in all21%
  5. Sierra CountyBest late August · 106 checklists that week, 8,945 in all21%
  6. Calaveras CountyBest early August · 127 checklists that week, 6,843 in all21%

Best spots

Share of checklists at the peak
  1. Mono Basin National Scenic AreaMono County, best mid August · 31 checklists that week, 1,309 in all97%
  2. Point San PabloContra Costa County, best early August · 21 checklists that week, 455 in all94%
  3. Harkins SloughSanta Cruz County, best late June · 21 checklists that week, 732 in all94%
  4. Clear Lake State ParkLake County, best the second week of March · 20 checklists that week, 637 in all92%

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

Best time of day

In California, the Osprey is most often listed on checklists started between 8 and 10 am (6.1% 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: 5.8% of 186053 checklists7 am: 5.9% of 444086 checklists8 am: 6.2% of 535846 checklists9 am: 6.1% of 486061 checklists10 am: 5.9% of 411130 checklists11 am: 5.7% of 325798 checklists12 pm: 5.5% of 269132 checklists1 pm: 5.5% of 244762 checklists2 pm: 5.5% of 235420 checklists3 pm: 4.9% of 232365 checklists4 pm: 4.3% of 208688 checklists5 pm: 4.1% of 146104 checklists6 pm: 3.5% 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
January5.1%4.9%5.0%4.5%
February4.3%4.1%4.0%4.9%
March4.8%5.0%5.3%5.2%
April5.6%5.2%5.3%5.3%
May5.1%5.1%5.2%5.4%
June5.4%5.9%6.3%6.3%
July6.4%6.7%7.1%7.4%
August7.9%8.1%8.1%7.8%
September7.4%6.5%5.9%5.3%
October5.2%5.3%4.9%5.1%
November5.4%5.3%5.0%5.3%
December5.1%5.0%4.3%5.0%

Neighboring states

  • Nevada: summer visitor, peaks mid April
  • Utah: summer visitor, peaks late August
  • Arizona: summer visitor, peaks late September
  • Oregon: summer visitor, peaks mid August

Common questions

When do Ospreys arrive in California?
The Osprey is in California all year. It turns up on about 8.0% of checklists at its peak (the second week of August) and on 4.1% in its quietest week (the second week of February).
When do Ospreys leave California?
The Osprey does not leave California: it is reported all year, from 4.1% of checklists in the second week of February to 8.0% in the second week of August.
When is the best time to see a Osprey in California?
The Osprey is reported most often in the second week of August, on about 8.0% of California checklists.
Where in California are Ospreys seen most often?
By county, Lake County, Del Norte County, and Mono County have the highest peak reporting rates for the Osprey (counties with at least 200 checklists).