WhenToBird

Mareca strepera · Anatidae

When Do Gadwalls Arrive in Illinois?

Adult Gadwall
Photo: Anne Parsons, CC0 1.0 via iNaturalist

Gadwalls are winter birds in Illinois: the first arrive in late September, they are common by the second week of October, peak in the second week of March (8.8% of checklists), and most are gone by mid April.

When to look

First arrivalsSep 22-30late September
Common byOct 8-14the second week of October
PeakMar 8-14the second week of March
Most gone byApr 15-21mid April

Best: the second week of March. First arrivals late September; most are gone by mid April. Peak: on about 8.8% of Illinois checklists.

  1. Jancommon
  2. Febcommon
  3. Marpeak season
  4. Aprcommon
  5. Mayrare
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Seprare
  10. Octcommon
  11. Novpeak season
  12. Deccommon

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

0%5%10%Jan 1-7: 4.5% of 29700 checklistsJan 8-14: 3.9% of 20189 checklistsJan 15-21: 3.7% of 19784 checklistsJan 22-31: 3.7% of 26641 checklistsFeb 1-7: 4.7% of 20478 checklistsFeb 8-14: 3.7% of 21967 checklistsFeb 15-21: 4.0% of 28735 checklistsFeb 22-28: 6.9% of 24223 checklistsMar 1-7: 8.1% of 26775 checklistsMar 8-14: 9.2% of 27579 checklistsMar 15-21: 9.1% of 27193 checklistsMar 22-31: 8.2% of 42278 checklistsApr 1-7: 6.0% of 34579 checklistsApr 8-14: 4.7% of 38290 checklistsApr 15-21: 3.6% of 39261 checklistsApr 22-30: 2.1% of 59584 checklistsMay 1-7: 1.0% of 60485 checklistsMay 8-14: 0.6% of 59647 checklistsMay 15-21: 0.4% of 43173 checklistsMay 22-31: 0.4% of 47913 checklistsJun 1-7: 0.3% of 31151 checklistsJun 8-14: 0.2% of 27692 checklistsJun 15-21: 0.2% of 23983 checklistsJun 22-30: 0.1% of 28448 checklistsJul 1-7: 0.1% of 21273 checklistsJul 8-14: 0.1% of 19284 checklistsJul 15-21: 0.1% of 17712 checklistsJul 22-31: 0.1% of 24500 checklistsAug 1-7: 0.1% of 18498 checklistsAug 8-14: 0.2% of 19331 checklistsAug 15-21: 0.2% of 19983 checklistsAug 22-31: 0.3% of 31892 checklistsSep 1-7: 0.4% of 26396 checklistsSep 8-14: 0.4% of 25011 checklistsSep 15-21: 0.4% of 23597 checklistsSep 22-30: 1.2% of 30638 checklistsOct 1-7: 2.0% of 23949 checklistsOct 8-14: 3.0% of 24412 checklistsOct 15-21: 5.2% of 22359 checklistsOct 22-31: 6.5% of 29794 checklistsNov 1-7: 7.6% of 21877 checklistsNov 8-14: 7.4% of 19742 checklistsNov 15-21: 6.8% of 18989 checklistsNov 22-30: 6.1% of 23905 checklistsDec 1-7: 5.8% of 16935 checklistsDec 8-14: 5.2% of 16687 checklistsDec 15-21: 3.9% of 20931 checklistsDec 22-31: 3.9% of 29011 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 Illinois 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 Illinois

Best counties

Share of checklists at the peak
  1. Putnam CountyBest late October · 91 checklists that week, 3,333 in all67%
  2. Edgar CountyBest mid January · 15 checklists that week, 914 in all61%
  3. Fulton CountyBest mid November · 46 checklists that week, 5,877 in all58%
  4. Perry CountyBest the second week of January · 17 checklists that week, 783 in all57%
  5. Wayne CountyBest the second week of November · 12 checklists that week, 394 in all55%
  6. Carroll CountyBest the second week of November · 36 checklists that week, 4,152 in all47%

Best spots

Share of checklists at the peak
  1. Des Plaines State Fish and Wildlife AreaWill County, best mid November · 40 checklists that week, 1,300 in all91%
  2. Horshoe Lake State ParkMadison County, best mid December · 58 checklists that week, 3,683 in all91%
  3. Frontage Road PondWill County, best early March · 20 checklists that week, 490 in all85%
  4. Twin LakesLake County, best early April · 35 checklists that week, 850 in all84%
  5. Lake ArispieBureau County, best late March · 28 checklists that week, 787 in all84%

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

Best time of day

In Illinois, the Gadwall is most often listed on checklists started between 1 and 3 pm (4.1% of those checklists).

0%2%4%6%12 am: too few checklists (484) to judge1 am: too few checklists (631) to judge2 am: too few checklists (485) to judge3 am: too few checklists (610) to judge4 am: too few checklists (2321) to judge5 am: too few checklists (23536) to judge6 am: 1.7% of 95511 checklists7 am: 2.8% of 164584 checklists8 am: 3.1% of 163654 checklists9 am: 3.4% of 141804 checklists10 am: 3.7% of 122882 checklists11 am: 3.9% of 100640 checklists12 pm: 3.8% of 89894 checklists1 pm: 4.0% of 82729 checklists2 pm: 4.2% of 79801 checklists3 pm: 3.8% of 82169 checklists4 pm: 3.0% of 75124 checklists5 pm: 2.1% of 57708 checklists6 pm: 1.3% of 41843 checklists7 pm: too few checklists (20943) to judge8 pm: too few checklists (6131) to judge9 pm: too few checklists (1677) to judge10 pm: too few checklists (843) to judge11 pm: too few checklists (448) 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
January4.5%3.9%3.7%3.7%
February4.7%3.7%4.0%6.9%
March8.1%9.2%9.1%8.2%
April6.0%4.7%3.6%2.1%
May1.0%0.6%0.4%0.4%
June0.3%0.2%0.2%0.1%
July0.1%0.1%0.1%0.1%
August0.1%0.2%0.2%0.3%
September0.4%0.4%0.4%1.2%
October2.0%3.0%5.2%6.5%
November7.6%7.4%6.8%6.1%
December5.8%5.2%3.9%3.9%

Neighboring states

  • Indiana: arrives early October, 1 week later than Illinois
  • Wisconsin: arrives late September, in the same week than Illinois
  • Michigan: arrives late September, in the same week than Illinois
  • Iowa: arrives the second week of February, 18 weeks later than Illinois

Common questions

When do Gadwalls arrive in Illinois?
Gadwalls are winter birds in Illinois: the first arrive in late September, they are common by the second week of October, peak in the second week of March (8.8% of checklists), and most are gone by mid April.
When do Gadwalls leave Illinois?
Most Gadwalls have left Illinois by mid April, when reports fall below half their usual rate. Stragglers are still reported until early May.
When is the best time to see a Gadwall in Illinois?
The Gadwall is reported most often in the second week of March, on about 8.8% of Illinois checklists.
Where in Illinois are Gadwalls seen most often?
By county, Putnam County, Edgar County, and Fulton County have the highest peak reporting rates for the Gadwall (counties with at least 200 checklists).