WhenToBird

Mareca strepera · Anatidae

When Do Gadwalls Arrive in South Dakota?

Adult Gadwall
Photo: Anne Parsons, CC0 1.0 via iNaturalist

Gadwalls are in South Dakota all year, but most are here in spring: numbers build from the second week of March, peak in the second week of April (24% of checklists), and fall back by early May. In the quietest week (late July) they are still on about 2.6% of checklists.

When to look

Numbers buildMar 8-14the second week of March
PeakApr 8-14the second week of April
Fall back byMay 1-7early May
FewestJul 22-31late July

Best: the second week of April. Here all year; numbers build from the second week of March and fall back by early May. Peak: on about 24% of South Dakota checklists.

  1. Januncommon
  2. Febuncommon
  3. Marpeak season
  4. Aprpeak season
  5. Maycommon
  6. Jununcommon
  7. Juluncommon
  8. Augrare
  9. Sepuncommon
  10. Octcommon
  11. Novcommon
  12. Decuncommon

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

0%10%20%30%Jan 1-7: 4.2% of 1699 checklistsJan 8-14: 4.7% of 967 checklistsJan 15-21: 4.9% of 893 checklistsJan 22-31: 6.1% of 1338 checklistsFeb 1-7: 5.1% of 898 checklistsFeb 8-14: 4.5% of 1013 checklistsFeb 15-21: 3.7% of 1650 checklistsFeb 22-28: 5.1% of 1011 checklistsMar 1-7: 9.9% of 1304 checklistsMar 8-14: 15% of 1447 checklistsMar 15-21: 21% of 1524 checklistsMar 22-31: 22% of 2850 checklistsApr 1-7: 24% of 2170 checklistsApr 8-14: 23% of 2259 checklistsApr 15-21: 25% of 2578 checklistsApr 22-30: 20% of 3858 checklistsMay 1-7: 14% of 3532 checklistsMay 8-14: 10% of 4498 checklistsMay 15-21: 10% of 4211 checklistsMay 22-31: 9.4% of 5094 checklistsJun 1-7: 7.0% of 3279 checklistsJun 8-14: 6.6% of 3503 checklistsJun 15-21: 5.7% of 2861 checklistsJun 22-30: 6.1% of 3893 checklistsJul 1-7: 4.6% of 2666 checklistsJul 8-14: 2.9% of 2554 checklistsJul 15-21: 2.7% of 2412 checklistsJul 22-31: 2.4% of 2746 checklistsAug 1-7: 2.8% of 1842 checklistsAug 8-14: 3.2% of 1899 checklistsAug 15-21: 3.6% of 1757 checklistsAug 22-31: 2.8% of 2464 checklistsSep 1-7: 3.6% of 1894 checklistsSep 8-14: 3.0% of 1794 checklistsSep 15-21: 3.3% of 1671 checklistsSep 22-30: 4.4% of 2085 checklistsOct 1-7: 7.6% of 1429 checklistsOct 8-14: 9.6% of 1441 checklistsOct 15-21: 10% of 1330 checklistsOct 22-31: 14% of 1471 checklistsNov 1-7: 15% of 1168 checklistsNov 8-14: 13% of 1068 checklistsNov 15-21: 11% of 985 checklistsNov 22-30: 9.0% of 1108 checklistsDec 1-7: 7.8% of 890 checklistsDec 8-14: 7.9% of 957 checklistsDec 15-21: 7.3% of 1246 checklistsDec 22-31: 4.7% of 1514 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 South Dakota 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 South Dakota

Best counties

Share of checklists at the peak
  1. Hyde CountyBest late May · 10 checklists that week, 241 in all72%
  2. Edmunds CountyBest late June · 13 checklists that week, 466 in all57%
  3. Sully CountyBest mid June · 11 checklists that week, 632 in all56%
  4. Union CountyBest the second week of November · 10 checklists that week, 882 in all52%
  5. Campbell CountyBest mid May · 10 checklists that week, 212 in all52%
  6. Aurora CountyBest late March · 15 checklists that week, 348 in all50%

Best spots

Share of checklists at the peak
  1. Canyon Lake ParkPennington County, best late October · 71 checklists that week, 2,659 in all96%
  2. Lake YanktonYankton County, best late January · 22 checklists that week, 250 in all91%
  3. Farm IslandHughes County, best early April · 20 checklists that week, 825 in all50%
  4. Oaha Recreation AreaStanley County, best late April · 23 checklists that week, 247 in all50%

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

Best time of day

In South Dakota, the Gadwall is most often listed on checklists started between 2 and 4 pm (11% of those checklists).

0%5%10%15%12 am: too few checklists (49) to judge1 am: too few checklists (44) to judge2 am: too few checklists (33) to judge3 am: too few checklists (59) to judge4 am: too few checklists (227) to judge5 am: too few checklists (1080) to judge6 am: 6.3% of 3387 checklists7 am: 12% of 7718 checklists8 am: 8.4% of 10342 checklists9 am: 8.4% of 10758 checklists10 am: 8.2% of 9123 checklists11 am: 8.3% of 7814 checklists12 pm: 9.2% of 6876 checklists1 pm: 9.9% of 6801 checklists2 pm: 11% of 6673 checklists3 pm: 11% of 6344 checklists4 pm: 9.9% of 6412 checklists5 pm: 11% of 5570 checklists6 pm: 10% of 4276 checklists7 pm: 9.1% of 3183 checklists8 pm: too few checklists (1499) to judge9 pm: too few checklists (329) to judge10 pm: too few checklists (82) to judge11 pm: too few checklists (42) 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
January4.2%4.7%4.9%6.1%
February5.1%4.5%3.7%5.1%
March9.9%15%21%22%
April24%23%25%20%
May14%10%10%9.4%
June7.0%6.6%5.7%6.1%
July4.6%2.9%2.7%2.4%
August2.8%3.2%3.6%2.8%
September3.6%3.0%3.3%4.4%
October7.6%9.6%10%14%
November15%13%11%9.0%
December7.8%7.9%7.3%4.7%

Neighboring states

  • Nebraska: arrives mid August, 21 weeks later than South Dakota
  • North Dakota: arrives early March, 1 week earlier than South Dakota
  • Minnesota: arrives mid February, 3 weeks earlier than South Dakota
  • Iowa: arrives the second week of February, 4 weeks earlier than South Dakota

Common questions

When do Gadwalls arrive in South Dakota?
Gadwalls are in South Dakota all year, but most are here in spring: numbers build from the second week of March, peak in the second week of April (24% of checklists), and fall back by early May. In the quietest week (late July) they are still on about 2.6% of checklists.
When do Gadwalls leave South Dakota?
Gadwalls never fully leave South Dakota: numbers fall back below half their usual rate by early May, but some are still reported in every week, about 2.6% of checklists at the low.
When is the best time to see a Gadwall in South Dakota?
The Gadwall is reported most often in the second week of April, on about 24% of South Dakota checklists.
Where in South Dakota are Gadwalls seen most often?
By county, Hyde County, Edmunds County, and Sully County have the highest peak reporting rates for the Gadwall (counties with at least 200 checklists).