WhenToBird

Tachycineta thalassina · Hirundinidae

When Do Violet-green Swallows Arrive in California?

Adult Violet-green Swallow
Photo: MarvalPhotography19, CC BY 4.0 via iNaturalist

Violet-green Swallows reach California in the second week of February, are common by the second week of March, peak in late May (14% of checklists), and most are gone by late July.

When to look

First arrivalsFeb 8-14the second week of February
Common byMar 8-14the second week of March
PeakMay 22-31late May
Most gone byJul 22-31late July

Best: late May. First arrivals the second week of February; most are gone by late July. Peak: on about 14% of California checklists.

  1. Janrare
  2. Febuncommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Auguncommon
  9. Sepuncommon
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%Jan 1-7: 0.7% of 112336 checklistsJan 8-14: 0.5% of 85518 checklistsJan 15-21: 0.5% of 86488 checklistsJan 22-31: 0.5% of 116174 checklistsFeb 1-7: 0.7% of 75171 checklistsFeb 8-14: 1.3% of 84467 checklistsFeb 15-21: 1.4% of 105683 checklistsFeb 22-28: 2.6% of 83396 checklistsMar 1-7: 4.7% of 77470 checklistsMar 8-14: 6.5% of 75180 checklistsMar 15-21: 7.8% of 80770 checklistsMar 22-31: 8.6% of 114116 checklistsApr 1-7: 9.3% of 84057 checklistsApr 8-14: 11% of 83692 checklistsApr 15-21: 11% of 89242 checklistsApr 22-30: 12% of 114289 checklistsMay 1-7: 13% of 85728 checklistsMay 8-14: 14% of 91984 checklistsMay 15-21: 14% of 75478 checklistsMay 22-31: 14% of 106250 checklistsJun 1-7: 14% of 70051 checklistsJun 8-14: 13% of 67485 checklistsJun 15-21: 15% of 66269 checklistsJun 22-30: 14% of 79172 checklistsJul 1-7: 13% of 62877 checklistsJul 8-14: 10% of 60328 checklistsJul 15-21: 8.0% of 59705 checklistsJul 22-31: 5.4% of 83796 checklistsAug 1-7: 3.9% of 60215 checklistsAug 8-14: 3.5% of 60172 checklistsAug 15-21: 3.4% of 59877 checklistsAug 22-31: 3.5% of 89107 checklistsSep 1-7: 3.4% of 72000 checklistsSep 8-14: 3.4% of 71228 checklistsSep 15-21: 3.4% of 76808 checklistsSep 22-30: 2.0% of 100204 checklistsOct 1-7: 1.8% of 76571 checklistsOct 8-14: 1.8% of 80874 checklistsOct 15-21: 1.1% of 74581 checklistsOct 22-31: 0.6% of 97498 checklistsNov 1-7: 0.3% of 70851 checklistsNov 8-14: 0.2% of 72431 checklistsNov 15-21: 0.3% of 66767 checklistsNov 22-30: 0.2% of 94737 checklistsDec 1-7: 0.3% of 65393 checklistsDec 8-14: 0.3% of 67449 checklistsDec 15-21: 0.4% of 83421 checklistsDec 22-31: 0.4% 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.

Embed this map on your site

Where in California

Best counties

Share of checklists at the peak
  1. Mendocino CountyBest early June · 918 checklists that week, 47,934 in all37%
  2. Humboldt CountyBest late May · 2516 checklists that week, 95,963 in all37%
  3. Santa Cruz CountyBest mid June · 2083 checklists that week, 140,819 in all36%
  4. Monterey CountyBest late May · 3170 checklists that week, 132,505 in all35%
  5. Napa CountyBest early May · 402 checklists that week, 18,976 in all33%
  6. Mono CountyBest the second week of July · 1267 checklists that week, 38,666 in all32%

Best spots

Share of checklists at the peak
  1. San Gabriel Mountains National Monument (Grassy Hollow)Los Angeles County, best mid June · 42 checklists that week, 723 in all95%
  2. Spring LakesSanta Cruz County, best the second week of June · 27 checklists that week, 1,599 in all95%
  3. Mono Basin National Scenic AreaMono County, best early July · 49 checklists that week, 1,309 in all94%
  4. Henry Cowell Redwoods State Park (Shingle Mill Creek)Santa Cruz County, best late May · 30 checklists that week, 349 in all93%
  5. Enid Pearson-Arastradero PreserveSanta Clara County, best late May · 54 checklists that week, 1,223 in all93%
  6. Hot SpringMono County, best mid July · 20 checklists that week, 756 in all93%

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

Best time of day

In California, the Violet-green Swallow is most often listed on checklists started between 8 and 10 am (6.5% 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: 6.6% of 186053 checklists7 am: 6.1% of 444086 checklists8 am: 6.7% of 535846 checklists9 am: 6.3% of 486061 checklists10 am: 5.5% of 411130 checklists11 am: 4.9% of 325798 checklists12 pm: 4.3% of 269132 checklists1 pm: 3.9% of 244762 checklists2 pm: 3.6% of 235420 checklists3 pm: 3.3% of 232365 checklists4 pm: 3.6% of 208688 checklists5 pm: 5.1% of 146104 checklists6 pm: 5.9% 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
January0.7%0.5%0.5%0.5%
February0.7%1.3%1.4%2.6%
March4.7%6.5%7.8%8.6%
April9.3%11%11%12%
May13%14%14%14%
June14%13%15%14%
July13%10%8.0%5.4%
August3.9%3.5%3.4%3.5%
September3.4%3.4%3.4%2.0%
October1.8%1.8%1.1%0.6%
November0.3%0.2%0.3%0.2%
December0.3%0.3%0.4%0.4%

Neighboring states

  • Nevada: arrives late February, 2 weeks later than California
  • Utah: arrives early April, 7 weeks later than California
  • Arizona: arrives the second week of February, in the same week than California
  • Oregon: arrives late February, 2 weeks later than California

Common questions

When do Violet-green Swallows arrive in California?
Violet-green Swallows reach California in the second week of February, are common by the second week of March, peak in late May (14% of checklists), and most are gone by late July.
When do Violet-green Swallows leave California?
Most Violet-green Swallows have left California by late July, when reports fall below half their usual rate. Stragglers are still reported until the second week of October.
When is the best time to see a Violet-green Swallow in California?
The Violet-green Swallow is reported most often in late May, on about 14% of California checklists.
Where in California are Violet-green Swallows seen most often?
By county, Mendocino County, Humboldt County, and Santa Cruz County have the highest peak reporting rates for the Violet-green Swallow (counties with at least 200 checklists).