WhenToBird

Setophaga nigrescens · Parulidae

When Do Black-throated Gray Warblers Arrive in California?

Adult Black-throated Gray Warbler
Photo: Dan Harville, CC BY-SA 4.0 via iNaturalist

Black-throated Gray Warblers reach California in early August, are common by the second week of August, peak in late September (6.3% of checklists), and most are gone by late October.

When to look

First arrivalsAug 1-7early August
Common byAug 8-14the second week of August
PeakSep 22-30late September
Most gone byOct 22-31late October

Best: late September. First arrivals early August; most are gone by late October. Peak: on about 6.3% of California checklists.

  1. Janrare
  2. Febrare
  3. Maruncommon
  4. Aprpeak season
  5. Maycommon
  6. Jununcommon
  7. Julrare
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novuncommon
  12. Decrare

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

0%2%4%6%8%Jan 1-7: 0.5% of 112336 checklistsJan 8-14: 0.5% of 85518 checklistsJan 15-21: 0.4% of 86488 checklistsJan 22-31: 0.3% of 116174 checklistsFeb 1-7: 0.3% of 75171 checklistsFeb 8-14: 0.3% of 84467 checklistsFeb 15-21: 0.3% of 105683 checklistsFeb 22-28: 0.4% of 83396 checklistsMar 1-7: 0.4% of 77470 checklistsMar 8-14: 0.3% of 75180 checklistsMar 15-21: 0.4% of 80770 checklistsMar 22-31: 1.0% of 114116 checklistsApr 1-7: 3.3% of 84057 checklistsApr 8-14: 4.7% of 83692 checklistsApr 15-21: 6.8% of 89242 checklistsApr 22-30: 6.2% of 114289 checklistsMay 1-7: 4.3% of 85728 checklistsMay 8-14: 2.8% of 91984 checklistsMay 15-21: 2.3% of 75478 checklistsMay 22-31: 2.0% of 106250 checklistsJun 1-7: 2.0% of 70051 checklistsJun 8-14: 1.8% of 67485 checklistsJun 15-21: 1.6% of 66269 checklistsJun 22-30: 1.2% of 79172 checklistsJul 1-7: 0.8% of 62877 checklistsJul 8-14: 0.7% of 60328 checklistsJul 15-21: 0.7% of 59705 checklistsJul 22-31: 0.8% of 83796 checklistsAug 1-7: 1.4% of 60215 checklistsAug 8-14: 1.8% of 60172 checklistsAug 15-21: 2.2% of 59877 checklistsAug 22-31: 3.3% of 89107 checklistsSep 1-7: 4.2% of 72000 checklistsSep 8-14: 4.8% of 71228 checklistsSep 15-21: 6.2% of 76808 checklistsSep 22-30: 6.6% of 100204 checklistsOct 1-7: 6.1% of 76571 checklistsOct 8-14: 4.6% of 80874 checklistsOct 15-21: 3.5% of 74581 checklistsOct 22-31: 1.9% of 97498 checklistsNov 1-7: 1.0% of 70851 checklistsNov 8-14: 0.6% of 72431 checklistsNov 15-21: 0.6% of 66767 checklistsNov 22-30: 0.6% of 94737 checklistsDec 1-7: 0.5% of 65393 checklistsDec 8-14: 0.5% of 67449 checklistsDec 15-21: 0.5% of 83421 checklistsDec 22-31: 0.5% 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. Yolo CountyBest early September · 1481 checklists that week, 67,424 in all29%
  2. Nevada CountyBest late April · 758 checklists that week, 25,896 in all17%
  3. Solano CountyBest the second week of September · 407 checklists that week, 25,325 in all17%
  4. Trinity CountyBest early May · 218 checklists that week, 9,037 in all16%
  5. Mariposa CountyBest the second week of May · 611 checklists that week, 17,385 in all15%
  6. Kings CountyBest late September · 123 checklists that week, 3,688 in all13%

Best spots

Share of checklists at the peak
  1. Auburn State Recreation AreaPlacer County, best late April · 32 checklists that week, 228 in all87%
  2. Lake FreySolano County, best late April · 22 checklists that week, 159 in all81%
  3. Eisenhower Park (Olive)Orange County, best late April · 50 checklists that week, 355 in all78%
  4. Palmer CreekHumboldt County, best early September · 23 checklists that week, 796 in all77%

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

Best time of day

In California, the Black-throated Gray Warbler is most often listed on checklists started between 6 and 8 am (3.7% of those checklists).

0%1%2%3%4%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: 3.9% of 186053 checklists7 am: 3.7% of 444086 checklists8 am: 2.9% of 535846 checklists9 am: 2.3% of 486061 checklists10 am: 1.9% of 411130 checklists11 am: 1.6% of 325798 checklists12 pm: 1.5% of 269132 checklists1 pm: 1.3% of 244762 checklists2 pm: 1.1% of 235420 checklists3 pm: 1.1% of 232365 checklists4 pm: 1.1% of 208688 checklists5 pm: 1.2% of 146104 checklists6 pm: 0.9% 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
January0.5%0.5%0.4%0.3%
February0.3%0.3%0.3%0.4%
March0.4%0.3%0.4%1.0%
April3.3%4.7%6.8%6.2%
May4.3%2.8%2.3%2.0%
June2.0%1.8%1.6%1.2%
July0.8%0.7%0.7%0.8%
August1.4%1.8%2.2%3.3%
September4.2%4.8%6.2%6.6%
October6.1%4.6%3.5%1.9%
November1.0%0.6%0.6%0.6%
December0.5%0.5%0.5%0.5%

Neighboring states

  • Nevada: arrives mid April, 14 weeks earlier than California
  • Utah: arrives mid April, 14 weeks earlier than California
  • Arizona: arrives early March, 20 weeks earlier than California
  • Oregon: arrives early April, 16 weeks earlier than California

Common questions

When do Black-throated Gray Warblers arrive in California?
Black-throated Gray Warblers reach California in early August, are common by the second week of August, peak in late September (6.3% of checklists), and most are gone by late October.
When do Black-throated Gray Warblers leave California?
Most Black-throated Gray Warblers have left California by late October, when reports fall below half their usual rate. Stragglers are still reported until early November.
When is the best time to see a Black-throated Gray Warbler in California?
The Black-throated Gray Warbler is reported most often in late September, on about 6.3% of California checklists.
Where in California are Black-throated Gray Warblers seen most often?
By county, Yolo County, Nevada County, and Solano County have the highest peak reporting rates for the Black-throated Gray Warbler (counties with at least 200 checklists).