WhenToBird

Falco peregrinus · Falconidae

When Do Peregrine Falcons Arrive in Wisconsin?

Adult Peregrine Falcon
Photo: Andrea Poggi, CC BY 4.0 via iNaturalist

Peregrine Falcons reach Wisconsin in mid July, are common by early August, peak in late September (1.4% of checklists), and most are gone by mid May.

When to look

First arrivalsJul 15-21mid July
Common byAug 1-7early August
PeakSep 22-30late September
Most gone byMay 15-21mid May

Best: late September. First arrivals mid July; most are gone by mid May. Peak: on about 1.4% of Wisconsin checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Apruncommon
  5. Mayuncommon
  6. Jununcommon
  7. Juluncommon
  8. Augcommon
  9. Seppeak season
  10. Octpeak season
  11. Novuncommon
  12. Decuncommon

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

0%0.5%1%1.5%2%Jan 1-7: 0.6% of 27925 checklistsJan 8-14: 0.6% of 18337 checklistsJan 15-21: 0.6% of 17370 checklistsJan 22-31: 0.7% of 23777 checklistsFeb 1-7: 0.5% of 16656 checklistsFeb 8-14: 0.4% of 18286 checklistsFeb 15-21: 0.3% of 24739 checklistsFeb 22-28: 0.7% of 20113 checklistsMar 1-7: 0.9% of 24024 checklistsMar 8-14: 0.7% of 26722 checklistsMar 15-21: 0.6% of 27238 checklistsMar 22-31: 0.5% of 40171 checklistsApr 1-7: 0.4% of 34961 checklistsApr 8-14: 0.4% of 39128 checklistsApr 15-21: 0.4% of 38887 checklistsApr 22-30: 0.5% of 57231 checklistsMay 1-7: 0.5% 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: 0.3% of 31282 checklistsJun 15-21: 0.2% of 30186 checklistsJun 22-30: 0.3% of 35128 checklistsJul 1-7: 0.3% of 27088 checklistsJul 8-14: 0.3% of 23293 checklistsJul 15-21: 0.3% of 20933 checklistsJul 22-31: 0.4% of 27595 checklistsAug 1-7: 0.5% of 19147 checklistsAug 8-14: 0.7% of 18286 checklistsAug 15-21: 0.8% of 19195 checklistsAug 22-31: 0.9% of 28229 checklistsSep 1-7: 0.9% of 22408 checklistsSep 8-14: 0.8% of 20857 checklistsSep 15-21: 1.3% of 20707 checklistsSep 22-30: 1.6% of 26469 checklistsOct 1-7: 1.2% of 21069 checklistsOct 8-14: 0.9% of 21011 checklistsOct 15-21: 0.7% of 20006 checklistsOct 22-31: 0.6% of 26362 checklistsNov 1-7: 0.5% of 18928 checklistsNov 8-14: 0.4% of 17052 checklistsNov 15-21: 0.4% of 16291 checklistsNov 22-30: 0.4% of 20564 checklistsDec 1-7: 0.3% of 15354 checklistsDec 8-14: 0.5% of 16294 checklistsDec 15-21: 0.5% of 21430 checklistsDec 22-31: 0.4% 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. Pepin CountyBest the second week of October · 12 checklists that week, 929 in all16%
  2. Douglas CountyBest late September · 760 checklists that week, 14,015 in all10%
  3. Ozaukee CountyBest early October · 606 checklists that week, 38,294 in all7.4%
  4. Brown CountyBest mid August · 679 checklists that week, 36,306 in all5.4%
  5. Kewaunee CountyBest late January · 157 checklists that week, 9,747 in all4.8%
  6. Kenosha CountyBest the second week of October · 142 checklists that week, 11,654 in all4.7%

Best spots

Share of checklists at the peak
  1. South BeachOzaukee County, best late September · 61 checklists that week, 157 in all58%
  2. Manitowoc RiverManitowoc County, best early March · 23 checklists that week, 771 in all50%
  3. Coal Dock ParkOzaukee County, best early March · 97 checklists that week, 1,961 in all38%

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

Best time of day

In Wisconsin, the Peregrine Falcon is most often listed on checklists started between 12 and 2 pm (0.6% of those checklists).

0%0.5%1%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: 0.3% of 27016 checklists6 am: 0.5% of 83973 checklists7 am: 0.5% of 160717 checklists8 am: 0.6% of 160531 checklists9 am: 0.6% of 136968 checklists10 am: 0.6% of 119110 checklists11 am: 0.6% of 99116 checklists12 pm: 0.6% of 85078 checklists1 pm: 0.6% of 80688 checklists2 pm: 0.6% of 79140 checklists3 pm: 0.6% of 78599 checklists4 pm: 0.5% of 69767 checklists5 pm: 0.5% of 53229 checklists6 pm: 0.5% 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
January0.6%0.6%0.6%0.7%
February0.5%0.4%0.3%0.7%
March0.9%0.7%0.6%0.5%
April0.4%0.4%0.4%0.5%
May0.5%0.4%0.5%0.4%
June0.3%0.3%0.2%0.3%
July0.3%0.3%0.3%0.4%
August0.5%0.7%0.8%0.9%
September0.9%0.8%1.3%1.6%
October1.2%0.9%0.7%0.6%
November0.5%0.4%0.4%0.4%
December0.3%0.5%0.5%0.4%

Neighboring states

  • Illinois: arrives mid June, 4 weeks earlier than Wisconsin
  • Iowa: arrives mid July, in the same week than Wisconsin
  • Michigan: arrives early July, 2 weeks earlier than Wisconsin
  • Minnesota: arrives late February, 19 weeks earlier than Wisconsin

Common questions

When do Peregrine Falcons arrive in Wisconsin?
Peregrine Falcons reach Wisconsin in mid July, are common by early August, peak in late September (1.4% of checklists), and most are gone by mid May.
When do Peregrine Falcons leave Wisconsin?
Most Peregrine Falcons have left Wisconsin by mid May, when reports fall below half their usual rate. Stragglers are still reported until early June.
When is the best time to see a Peregrine Falcon in Wisconsin?
The Peregrine Falcon is reported most often in late September, on about 1.4% of Wisconsin checklists.
Where in Wisconsin are Peregrine Falcons seen most often?
By county, Pepin County, Douglas County, and Ozaukee County have the highest peak reporting rates for the Peregrine Falcon (counties with at least 200 checklists).