WhenToBird

Passerina caerulea · Cardinalidae

When Do Blue Grosbeaks Arrive in California?

Adult male Blue Grosbeak
Photo: John Rosford, CC BY 4.0 via iNaturalist

Blue Grosbeaks arrive in California in mid April, peak in the second week of May (2.3% of checklists), and most are gone by the second week of August.

When to look

First arrivalsApr 15-21mid April
Common byApr 15-21mid April
PeakMay 8-14the second week of May
Most gone byAug 8-14the second week of August

Best: the second week of May. First arrivals mid April; most are gone by the second week of August. Peak: on about 2.3% of California checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepuncommon
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%1%2%3%Jan 1-7: 0% of 112336 checklistsJan 8-14: 0.1% of 85518 checklistsJan 15-21: 0.1% of 86488 checklistsJan 22-31: 0.1% of 116174 checklistsFeb 1-7: 0.1% of 75171 checklistsFeb 8-14: 0% of 84467 checklistsFeb 15-21: 0.1% of 105683 checklistsFeb 22-28: 0% of 83396 checklistsMar 1-7: 0% of 77470 checklistsMar 8-14: 0% of 75180 checklistsMar 15-21: 0% of 80770 checklistsMar 22-31: 0.1% of 114116 checklistsApr 1-7: 0.1% of 84057 checklistsApr 8-14: 0.2% of 83692 checklistsApr 15-21: 1.1% of 89242 checklistsApr 22-30: 1.9% of 114289 checklistsMay 1-7: 2.4% of 85728 checklistsMay 8-14: 2.2% of 91984 checklistsMay 15-21: 2.3% of 75478 checklistsMay 22-31: 2.3% of 106250 checklistsJun 1-7: 2.1% of 70051 checklistsJun 8-14: 1.9% of 67485 checklistsJun 15-21: 2.0% of 66269 checklistsJun 22-30: 2.0% of 79172 checklistsJul 1-7: 2.0% of 62877 checklistsJul 8-14: 2.0% of 60328 checklistsJul 15-21: 1.9% of 59705 checklistsJul 22-31: 1.7% of 83796 checklistsAug 1-7: 1.4% of 60215 checklistsAug 8-14: 1.0% of 60172 checklistsAug 15-21: 0.7% of 59877 checklistsAug 22-31: 0.6% of 89107 checklistsSep 1-7: 0.4% of 72000 checklistsSep 8-14: 0.3% of 71228 checklistsSep 15-21: 0.2% of 76808 checklistsSep 22-30: 0.2% of 100204 checklistsOct 1-7: 0.1% of 76571 checklistsOct 8-14: 0.1% of 80874 checklistsOct 15-21: 0.1% of 74581 checklistsOct 22-31: 0.1% of 97498 checklistsNov 1-7: 0.1% of 70851 checklistsNov 8-14: 0.1% of 72431 checklistsNov 15-21: 0.1% of 66767 checklistsNov 22-30: 0.1% of 94737 checklistsDec 1-7: 0.1% of 65393 checklistsDec 8-14: 0.1% of 67449 checklistsDec 15-21: 0% of 83421 checklistsDec 22-31: 0.1% 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. Kings CountyBest late May · 99 checklists that week, 3,688 in all18%
  2. Inyo CountyBest late May · 1654 checklists that week, 35,713 in all9.1%
  3. Glenn CountyBest early July · 80 checklists that week, 5,189 in all8.8%
  4. Colusa CountyBest mid June · 75 checklists that week, 7,653 in all8.6%
  5. Yolo CountyBest late July · 1189 checklists that week, 67,424 in all7.8%
  6. Riverside CountyBest early July · 1315 checklists that week, 113,541 in all7.3%

Best spots

Share of checklists at the peak
  1. Sacramento Regional County Sanitation DistrictSacramento County, best mid July · 47 checklists that week, 2,065 in all97%
  2. Palo Verde Ecological ReserveRiverside County, best the second week of July · 20 checklists that week, 740 in all83%
  3. Fairview ParkOrange County, best early July · 24 checklists that week, 1,494 in all81%

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

Best time of day

In California, the Blue Grosbeak is most often listed on checklists started between 6 and 8 am (1.5% of those checklists).

0%0.5%1%1.5%2%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: 2.0% of 186053 checklists7 am: 1.2% of 444086 checklists8 am: 0.9% of 535846 checklists9 am: 0.6% of 486061 checklists10 am: 0.4% of 411130 checklists11 am: 0.3% of 325798 checklists12 pm: 0.3% of 269132 checklists1 pm: 0.3% of 244762 checklists2 pm: 0.2% of 235420 checklists3 pm: 0.2% of 232365 checklists4 pm: 0.3% of 208688 checklists5 pm: 0.5% of 146104 checklists6 pm: 0.6% 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%0.1%0.1%0.1%
February0.1%0%0.1%0%
March0%0%0%0.1%
April0.1%0.2%1.1%1.9%
May2.4%2.2%2.3%2.3%
June2.1%1.9%2.0%2.0%
July2.0%2.0%1.9%1.7%
August1.4%1.0%0.7%0.6%
September0.4%0.3%0.2%0.2%
October0.1%0.1%0.1%0.1%
November0.1%0.1%0.1%0.1%
December0.1%0.1%0%0.1%

Neighboring states

  • Nevada: arrives late April, 1 week later than California
  • Utah: arrives mid May, 4 weeks later than California
  • Arizona: arrives early May, 2 weeks later than California
  • New Mexico: arrives early May, 2 weeks later than California

Common questions

When do Blue Grosbeaks arrive in California?
Blue Grosbeaks arrive in California in mid April, peak in the second week of May (2.3% of checklists), and most are gone by the second week of August.
When do Blue Grosbeaks leave California?
Most Blue Grosbeaks have left California by the second week of August, when reports fall below half their usual rate.
When is the best time to see a Blue Grosbeak in California?
The Blue Grosbeak is reported most often in the second week of May, on about 2.3% of California checklists.
Where in California are Blue Grosbeaks seen most often?
By county, Kings County, Inyo County, and Glenn County have the highest peak reporting rates for the Blue Grosbeak (counties with at least 200 checklists).