WhenToBird

Aythya marila · Anatidae

When Do Greater Scaups Arrive in Wisconsin?

Adult Greater Scaup
Photo: Se Lena, CC BY 4.0 via iNaturalist

Greater Scaups are winter birds in Wisconsin: the first arrive in mid October, they are common by late October, peak in early March (4.1% of checklists), and most are gone by late April.

When to look

First arrivalsOct 15-21mid October
Common byOct 22-31late October
PeakMar 1-7early March
Most gone byApr 22-30late April

Best: early March. First arrivals mid October; most are gone by late April. Peak: on about 4.1% of Wisconsin checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Aprcommon
  5. Mayuncommon
  6. Junrare
  7. Julrare
  8. Augnot usually seen
  9. Seprare
  10. Octuncommon
  11. Novcommon
  12. Decpeak season

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

0%2%4%6%Jan 1-7: 4.2% of 27925 checklistsJan 8-14: 4.3% of 18337 checklistsJan 15-21: 3.7% of 17370 checklistsJan 22-31: 3.4% of 23777 checklistsFeb 1-7: 3.6% of 16656 checklistsFeb 8-14: 2.9% of 18286 checklistsFeb 15-21: 2.4% of 24739 checklistsFeb 22-28: 4.0% of 20113 checklistsMar 1-7: 4.6% of 24024 checklistsMar 8-14: 3.8% of 26722 checklistsMar 15-21: 3.6% of 27238 checklistsMar 22-31: 3.4% of 40171 checklistsApr 1-7: 2.8% of 34961 checklistsApr 8-14: 2.3% of 39128 checklistsApr 15-21: 2.4% of 38887 checklistsApr 22-30: 1.6% of 57231 checklistsMay 1-7: 0.9% of 55115 checklistsMay 8-14: 0.4% of 63098 checklistsMay 15-21: 0.5% of 49821 checklistsMay 22-31: 0.4% of 56796 checklistsJun 1-7: 0.3% of 33621 checklistsJun 8-14: 0.2% of 31282 checklistsJun 15-21: 0.1% of 30186 checklistsJun 22-30: 0.2% of 35128 checklistsJul 1-7: 0.2% of 27088 checklistsJul 8-14: 0.2% of 23293 checklistsJul 15-21: 0.1% of 20933 checklistsJul 22-31: 0.1% of 27595 checklistsAug 1-7: 0.1% of 19147 checklistsAug 8-14: 0.1% of 18286 checklistsAug 15-21: 0.2% of 19195 checklistsAug 22-31: 0.1% of 28229 checklistsSep 1-7: 0.1% of 22408 checklistsSep 8-14: 0.1% of 20857 checklistsSep 15-21: 0.2% of 20707 checklistsSep 22-30: 0.5% of 26469 checklistsOct 1-7: 0.5% of 21069 checklistsOct 8-14: 0.7% of 21011 checklistsOct 15-21: 1.2% of 20006 checklistsOct 22-31: 1.6% of 26362 checklistsNov 1-7: 2.0% of 18928 checklistsNov 8-14: 2.0% of 17052 checklistsNov 15-21: 1.9% of 16291 checklistsNov 22-30: 2.0% of 20564 checklistsDec 1-7: 2.1% of 15354 checklistsDec 8-14: 2.1% of 16294 checklistsDec 15-21: 2.3% of 21430 checklistsDec 22-31: 2.8% of 26314 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 Wisconsin 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 Wisconsin

Best counties

Share of checklists at the peak
  1. Kewaunee CountyBest early March · 165 checklists that week, 9,747 in all48%
  2. Milwaukee CountyBest the second week of January · 2012 checklists that week, 114,667 in all22%
  3. Manitowoc CountyBest early March · 501 checklists that week, 26,017 in all21%
  4. Brown CountyBest early April · 1093 checklists that week, 36,306 in all19%
  5. Oconto CountyBest mid November · 136 checklists that week, 8,609 in all18%
  6. Sheboygan CountyBest late February · 431 checklists that week, 25,419 in all17%

Best spots

Share of checklists at the peak
  1. KewauneeKewaunee County, best early March · 72 checklists that week, 2,215 in all95%
  2. Jones IslandMilwaukee County, best early March · 20 checklists that week, 779 in all89%
  3. O'Donnell ParkMilwaukee County, best early March · 23 checklists that week, 604 in all88%
  4. Pugh Recreational AreaRacine County, best late February · 29 checklists that week, 645 in all87%
  5. Dead Horse BayBrown County, best early April · 39 checklists that week, 630 in all87%
  6. Public SquareManitowoc County, best the second week of March · 37 checklists that week, 590 in all86%

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

Best time of day

In Wisconsin, the Greater Scaup is most often listed on checklists started between 12 and 2 pm (2.2% of those checklists).

0%1%2%3%12 am: too few checklists (993) to judge1 am: too few checklists (844) to judge2 am: too few checklists (839) to judge3 am: too few checklists (1488) to judge4 am: too few checklists (5344) to judge5 am: 0.4% of 27016 checklists6 am: 1.0% of 83973 checklists7 am: 1.0% of 160717 checklists8 am: 1.3% of 160531 checklists9 am: 1.6% of 136968 checklists10 am: 1.9% of 119110 checklists11 am: 2.2% of 99116 checklists12 pm: 2.2% of 85078 checklists1 pm: 2.2% of 80688 checklists2 pm: 2.2% of 79140 checklists3 pm: 2.0% of 78599 checklists4 pm: 1.5% of 69767 checklists5 pm: 1.0% of 53229 checklists6 pm: 0.7% of 38769 checklists7 pm: too few checklists (24396) to judge8 pm: too few checklists (10155) to judge9 pm: too few checklists (4990) to judge10 pm: too few checklists (2463) to judge11 pm: too few checklists (1281) 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%4.3%3.7%3.4%
February3.6%2.9%2.4%4.0%
March4.6%3.8%3.6%3.4%
April2.8%2.3%2.4%1.6%
May0.9%0.4%0.5%0.4%
June0.3%0.2%0.1%0.2%
July0.2%0.2%0.1%0.1%
August0.1%0.1%0.2%0.1%
September0.1%0.1%0.2%0.5%
October0.5%0.7%1.2%1.6%
November2.0%2.0%1.9%2.0%
December2.1%2.1%2.3%2.8%

Neighboring states

  • Illinois: arrives early November, 2 weeks later than Wisconsin
  • Iowa: arrives mid November, 4 weeks later than Wisconsin
  • Michigan: arrives the second week of October, 1 week earlier than Wisconsin
  • Minnesota: arrives early March, 18 weeks later than Wisconsin

Common questions

When do Greater Scaups arrive in Wisconsin?
Greater Scaups are winter birds in Wisconsin: the first arrive in mid October, they are common by late October, peak in early March (4.1% of checklists), and most are gone by late April.
When do Greater Scaups leave Wisconsin?
Most Greater Scaups have left Wisconsin by late April, when reports fall below half their usual rate.
When is the best time to see a Greater Scaup in Wisconsin?
The Greater Scaup is reported most often in early March, on about 4.1% of Wisconsin checklists.
Where in Wisconsin are Greater Scaups seen most often?
By county, Kewaunee County, Milwaukee County, and Manitowoc County have the highest peak reporting rates for the Greater Scaup (counties with at least 200 checklists).