WhenToBird

Mareca strepera · Anatidae

When Do Gadwalls Arrive in California?

Adult Gadwall
Photo: Anne Parsons, CC0 1.0 via iNaturalist

The Gadwall is in California all year. It turns up on about 9.3% of checklists at its peak (the second week of January) and on 3.0% in its quietest week (late July).

When to look

PresentAll year
Peak weekJan 8-14the second week of January
Quietest weekJul 22-31late July

Best: the second week of January. Here all year. Peak: on about 9.3% of California checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novpeak season
  12. Decpeak season

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

0%5%10%Jan 1-7: 9.6% of 112336 checklistsJan 8-14: 9.1% of 85518 checklistsJan 15-21: 9.2% of 86488 checklistsJan 22-31: 8.9% of 116174 checklistsFeb 1-7: 8.7% of 75171 checklistsFeb 8-14: 7.7% of 84467 checklistsFeb 15-21: 7.0% of 105683 checklistsFeb 22-28: 8.1% of 83396 checklistsMar 1-7: 8.4% of 77470 checklistsMar 8-14: 8.0% of 75180 checklistsMar 15-21: 7.3% of 80770 checklistsMar 22-31: 7.0% of 114116 checklistsApr 1-7: 7.0% of 84057 checklistsApr 8-14: 6.9% of 83692 checklistsApr 15-21: 7.0% of 89242 checklistsApr 22-30: 7.1% of 114289 checklistsMay 1-7: 7.4% of 85728 checklistsMay 8-14: 6.8% of 91984 checklistsMay 15-21: 6.7% of 75478 checklistsMay 22-31: 6.4% of 106250 checklistsJun 1-7: 6.3% of 70051 checklistsJun 8-14: 5.9% of 67485 checklistsJun 15-21: 5.1% of 66269 checklistsJun 22-30: 4.5% of 79172 checklistsJul 1-7: 3.7% of 62877 checklistsJul 8-14: 3.1% of 60328 checklistsJul 15-21: 2.9% of 59705 checklistsJul 22-31: 3.0% of 83796 checklistsAug 1-7: 3.0% of 60215 checklistsAug 8-14: 3.2% of 60172 checklistsAug 15-21: 3.7% of 59877 checklistsAug 22-31: 4.2% of 89107 checklistsSep 1-7: 4.5% of 72000 checklistsSep 8-14: 4.6% of 71228 checklistsSep 15-21: 4.6% of 76808 checklistsSep 22-30: 4.9% of 100204 checklistsOct 1-7: 5.2% of 76571 checklistsOct 8-14: 5.7% of 80874 checklistsOct 15-21: 6.3% of 74581 checklistsOct 22-31: 7.1% of 97498 checklistsNov 1-7: 7.4% of 70851 checklistsNov 8-14: 7.6% of 72431 checklistsNov 15-21: 8.2% of 66767 checklistsNov 22-30: 8.6% of 94737 checklistsDec 1-7: 9.2% of 65393 checklistsDec 8-14: 8.3% of 67449 checklistsDec 15-21: 7.4% of 83421 checklistsDec 22-31: 7.9% 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. Colusa CountyBest mid November · 204 checklists that week, 7,653 in all47%
  2. Glenn CountyBest the second week of January · 145 checklists that week, 5,189 in all33%
  3. Modoc CountyBest early November · 84 checklists that week, 6,138 in all32%
  4. Lassen CountyBest mid April · 254 checklists that week, 8,378 in all31%
  5. Kings CountyBest late May · 99 checklists that week, 3,688 in all28%
  6. Sierra CountyBest the second week of April · 74 checklists that week, 8,945 in all25%

Best spots

Share of checklists at the peak
  1. Guadalupe Creek ParkchainSanta Clara County, best late September · 32 checklists that week, 1,849 in all99%
  2. Santa Ana River Trail (Peralta Hills)Orange County, best early January · 23 checklists that week, 777 in all97%
  3. Colusa National Wildlife RefugeColusa County, best late March · 22 checklists that week, 1,370 in all96%
  4. Port Watsonville (historical)Santa Cruz County, best mid April · 21 checklists that week, 1,423 in all95%
  5. Santa Ana River TrailOrange County, best early January · 39 checklists that week, 1,289 in all95%

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

Best time of day

In California, the Gadwall is most often listed on checklists started between 1 and 3 pm (7.3% 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: 5.7% of 186053 checklists7 am: 6.8% of 444086 checklists8 am: 7.3% of 535846 checklists9 am: 7.0% of 486061 checklists10 am: 6.9% of 411130 checklists11 am: 6.8% of 325798 checklists12 pm: 6.6% of 269132 checklists1 pm: 7.2% of 244762 checklists2 pm: 7.4% of 235420 checklists3 pm: 7.1% of 232365 checklists4 pm: 6.1% of 208688 checklists5 pm: 5.2% of 146104 checklists6 pm: 4.5% 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
January9.6%9.1%9.2%8.9%
February8.7%7.7%7.0%8.1%
March8.4%8.0%7.3%7.0%
April7.0%6.9%7.0%7.1%
May7.4%6.8%6.7%6.4%
June6.3%5.9%5.1%4.5%
July3.7%3.1%2.9%3.0%
August3.0%3.2%3.7%4.2%
September4.5%4.6%4.6%4.9%
October5.2%5.7%6.3%7.1%
November7.4%7.6%8.2%8.6%
December9.2%8.3%7.4%7.9%

Neighboring states

  • Nevada: all year, most in winter, peaks mid April
  • Utah: summer visitor, peaks early April
  • Arizona: winter visitor, peaks late November
  • Oregon: all year, most in spring, peaks the second week of May

Common questions

When do Gadwalls arrive in California?
The Gadwall is in California all year. It turns up on about 9.3% of checklists at its peak (the second week of January) and on 3.0% in its quietest week (late July).
When do Gadwalls leave California?
The Gadwall does not leave California: it is reported all year, from 3.0% of checklists in late July to 9.3% in the second week of January.
When is the best time to see a Gadwall in California?
The Gadwall is reported most often in the second week of January, on about 9.3% of California checklists.
Where in California are Gadwalls seen most often?
By county, Colusa County, Glenn County, and Modoc County have the highest peak reporting rates for the Gadwall (counties with at least 200 checklists).