WhenToBird

Chordeiles minor · Caprimulgidae

When Do Common Nighthawks Arrive in Wisconsin?

Adult Common Nighthawk
Photo: Donald Davesne, CC BY 4.0 via iNaturalist

Common Nighthawks mostly pass through Wisconsin: they arrive in the second week of August, peak in late August (7.0% of checklists), and most are gone by mid September.

When to look

First arrivalsAug 8-14the second week of August
Common byAug 8-14the second week of August
PeakAug 22-31late August
Most gone bySep 15-21mid September

Best: late August. First arrivals the second week of August; most are gone by mid September. Peak: on about 7.0% of Wisconsin checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Mayuncommon
  6. Jununcommon
  7. Julrare
  8. Augpeak season
  9. Seppeak season
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%Jan 1-7: 0% of 27925 checklistsJan 8-14: 0% of 18337 checklistsJan 15-21: 0% of 17370 checklistsJan 22-31: 0% of 23777 checklistsFeb 1-7: 0% of 16656 checklistsFeb 8-14: 0% of 18286 checklistsFeb 15-21: 0% of 24739 checklistsFeb 22-28: 0% of 20113 checklistsMar 1-7: 0% of 24024 checklistsMar 8-14: 0% of 26722 checklistsMar 15-21: 0% of 27238 checklistsMar 22-31: 0% of 40171 checklistsApr 1-7: 0% of 34961 checklistsApr 8-14: 0% of 39128 checklistsApr 15-21: 0.1% of 38887 checklistsApr 22-30: 0.1% of 57231 checklistsMay 1-7: 0.1% of 55115 checklistsMay 8-14: 0.8% of 63098 checklistsMay 15-21: 2.2% of 49821 checklistsMay 22-31: 3.8% of 56796 checklistsJun 1-7: 1.2% of 33621 checklistsJun 8-14: 0.5% of 31282 checklistsJun 15-21: 0.4% of 30186 checklistsJun 22-30: 0.4% of 35128 checklistsJul 1-7: 0.4% of 27088 checklistsJul 8-14: 0.3% of 23293 checklistsJul 15-21: 0.4% of 20933 checklistsJul 22-31: 0.4% of 27595 checklistsAug 1-7: 0.5% of 19147 checklistsAug 8-14: 1.1% of 18286 checklistsAug 15-21: 4.0% of 19195 checklistsAug 22-31: 9.6% of 28229 checklistsSep 1-7: 6.3% of 22408 checklistsSep 8-14: 3.5% of 20857 checklistsSep 15-21: 1.4% of 20707 checklistsSep 22-30: 0.3% of 26469 checklistsOct 1-7: 0.2% of 21069 checklistsOct 8-14: 0.1% of 21011 checklistsOct 15-21: 0% of 20006 checklistsOct 22-31: 0.1% of 26362 checklistsNov 1-7: 0% of 18928 checklistsNov 8-14: 0% of 17052 checklistsNov 15-21: 0% of 16291 checklistsNov 22-30: 0% of 20564 checklistsDec 1-7: 0% of 15354 checklistsDec 8-14: 0% of 16294 checklistsDec 15-21: 0% of 21430 checklistsDec 22-31: 0% 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. Marquette CountyBest late August · 159 checklists that week, 3,706 in all24%
  2. Monroe CountyBest early September · 72 checklists that week, 3,836 in all20%
  3. Waupaca CountyBest late August · 179 checklists that week, 6,994 in all19%
  4. Washburn CountyBest late August · 273 checklists that week, 7,099 in all18%
  5. Lincoln CountyBest early September · 136 checklists that week, 8,013 in all15%
  6. Brown CountyBest late August · 936 checklists that week, 36,306 in all14%

Best spots

Share of checklists at the peak
  1. Green Field ParkMilwaukee County, best early August · 23 checklists that week, 1,655 in all43%
  2. Mirror LakeSauk County, best late August · 22 checklists that week, 599 in all29%
  3. Sunny Vale ParkMarathon County, best early September · 22 checklists that week, 410 in all24%
  4. Cherokee ParkDane County, best early September · 112 checklists that week, 4,238 in all23%
  5. Kettle Moraine State Forest-Southern Unit (southwest 4)Jefferson County, best late May · 39 checklists that week, 187 in all22%

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

Best time of day

In Wisconsin, the Common Nighthawk is most often listed on checklists started between 5 and 7 pm (3.7% of those checklists).

0%2%4%6%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: 1.1% of 27016 checklists6 am: 0.5% of 83973 checklists7 am: 0.3% of 160717 checklists8 am: 0.3% of 160531 checklists9 am: 0.2% of 136968 checklists10 am: 0.2% of 119110 checklists11 am: 0.2% of 99116 checklists12 pm: 0.3% of 85078 checklists1 pm: 0.3% of 80688 checklists2 pm: 0.4% of 79140 checklists3 pm: 0.6% of 78599 checklists4 pm: 1.3% of 69767 checklists5 pm: 2.5% of 53229 checklists6 pm: 5.3% 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
January0%0%0%0%
February0%0%0%0%
March0%0%0%0%
April0%0%0.1%0.1%
May0.1%0.8%2.2%3.8%
June1.2%0.5%0.4%0.4%
July0.4%0.3%0.4%0.4%
August0.5%1.1%4.0%9.6%
September6.3%3.5%1.4%0.3%
October0.2%0.1%0%0.1%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Illinois: arrives the second week of May, 12 weeks earlier than Wisconsin
  • Iowa: arrives the second week of May, 12 weeks earlier than Wisconsin
  • Michigan: arrives the second week of May, 12 weeks earlier than Wisconsin
  • Minnesota: arrives early August, 1 week earlier than Wisconsin

Common questions

When do Common Nighthawks arrive in Wisconsin?
Common Nighthawks mostly pass through Wisconsin: they arrive in the second week of August, peak in late August (7.0% of checklists), and most are gone by mid September.
When do Common Nighthawks leave Wisconsin?
Most Common Nighthawks have left Wisconsin by mid September, when reports fall below half their usual rate.
When is the best time to see a Common Nighthawk in Wisconsin?
The Common Nighthawk is reported most often in late August, on about 7.0% of Wisconsin checklists.
Where in Wisconsin are Common Nighthawks seen most often?
By county, Marquette County, Monroe County, and Waupaca County have the highest peak reporting rates for the Common Nighthawk (counties with at least 200 checklists).