WhenToBird

Falco peregrinus · Falconidae

When Do Peregrine Falcons Arrive in Iowa?

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

Peregrine Falcons arrive in Iowa in mid July, peak in late September (1.6% of checklists), and most are gone by late October.

When to look

First arrivalsJul 15-21mid July
Common byJul 15-21mid July
PeakSep 22-30late September
Most gone byOct 22-31late October

Best: late September. First arrivals mid July; most are gone by late October. Peak: on about 1.6% of Iowa checklists.

  1. Januncommon
  2. Febuncommon
  3. Maruncommon
  4. Aprcommon
  5. Maycommon
  6. Junrare
  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: 0.3% of 5551 checklistsJan 8-14: 0.4% of 3498 checklistsJan 15-21: 0.1% of 3803 checklistsJan 22-31: 0.4% of 4807 checklistsFeb 1-7: 0.2% of 3613 checklistsFeb 8-14: 0.4% of 4173 checklistsFeb 15-21: 0.2% of 5796 checklistsFeb 22-28: 0.1% of 4394 checklistsMar 1-7: 0.3% of 5295 checklistsMar 8-14: 0.3% of 5679 checklistsMar 15-21: 0.4% of 5418 checklistsMar 22-31: 0.2% of 8613 checklistsApr 1-7: 0.3% of 6970 checklistsApr 8-14: 0.4% of 7511 checklistsApr 15-21: 0.7% of 8321 checklistsApr 22-30: 1.0% of 11976 checklistsMay 1-7: 0.6% of 11725 checklistsMay 8-14: 0.5% of 12626 checklistsMay 15-21: 0.4% of 9372 checklistsMay 22-31: 0.2% of 10330 checklistsJun 1-7: 0.1% of 5472 checklistsJun 8-14: 0.2% of 4568 checklistsJun 15-21: 0.1% of 3870 checklistsJun 22-30: 0.2% of 4780 checklistsJul 1-7: 0.2% of 4201 checklistsJul 8-14: 0.3% of 3605 checklistsJul 15-21: 0.2% of 3621 checklistsJul 22-31: 0.4% of 5093 checklistsAug 1-7: 0.8% of 3931 checklistsAug 8-14: 0.5% of 3488 checklistsAug 15-21: 0.8% of 3802 checklistsAug 22-31: 0.7% of 6293 checklistsSep 1-7: 0.8% of 5328 checklistsSep 8-14: 1.0% of 4622 checklistsSep 15-21: 1.5% of 4367 checklistsSep 22-30: 1.8% of 6086 checklistsOct 1-7: 1.4% of 4708 checklistsOct 8-14: 0.8% of 4791 checklistsOct 15-21: 0.4% of 4429 checklistsOct 22-31: 0.3% of 5633 checklistsNov 1-7: 0.2% of 4090 checklistsNov 8-14: 0.2% of 3416 checklistsNov 15-21: 0% of 3398 checklistsNov 22-30: 0.1% of 4679 checklistsDec 1-7: 0.1% of 3442 checklistsDec 8-14: 0.1% of 3322 checklistsDec 15-21: 0.3% of 4619 checklistsDec 22-31: 0.2% of 5113 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 Iowa 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 Iowa

Best counties

Share of checklists at the peak
  1. Jackson CountyBest early October · 23 checklists that week, 1,765 in all8.7%
  2. Louisa CountyBest mid September · 24 checklists that week, 1,639 in all8.0%
  3. Des Moines CountyBest the second week of March · 90 checklists that week, 2,251 in all6.6%
  4. Cerro Gordo CountyBest mid September · 32 checklists that week, 1,853 in all6.6%
  5. Fayette CountyBest the second week of March · 60 checklists that week, 1,130 in all6.0%
  6. Allamakee CountyBest late September · 51 checklists that week, 2,607 in all5.5%

Best spots

Share of checklists at the peak
  1. Riverfront ParkwayScott County, best the second week of January · 24 checklists that week, 270 in all36%
  2. John Deere MarshDubuque County, best the second week of August · 28 checklists that week, 1,952 in all21%
  3. Eagle Point ParkDubuque County, best late September · 21 checklists that week, 380 in all14%
  4. Coralville Recreation Area (west)Johnson County, best late August · 20 checklists that week, 329 in all13%
  5. Hitchcock Nature AreaPottawattamie County, best late September · 35 checklists that week, 472 in all12%
  6. Grammer Grove Wildlife AreaMarshall County, best early October · 29 checklists that week, 766 in all12%

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

Best time of day

In Iowa, the Peregrine Falcon is most often listed on checklists started between 5 and 7 pm (0.6% of those checklists).

0%0.5%1%12 am: too few checklists (96) to judge1 am: too few checklists (99) to judge2 am: too few checklists (67) to judge3 am: too few checklists (82) to judge4 am: too few checklists (201) to judge5 am: too few checklists (1888) to judge6 am: 0.4% of 11313 checklists7 am: 0.5% of 25717 checklists8 am: 0.6% of 29755 checklists9 am: 0.5% of 28897 checklists10 am: 0.5% of 26343 checklists11 am: 0.5% of 21210 checklists12 pm: 0.5% of 17662 checklists1 pm: 0.5% of 16595 checklists2 pm: 0.3% of 16405 checklists3 pm: 0.4% of 17030 checklists4 pm: 0.4% of 17378 checklists5 pm: 0.7% of 14251 checklists6 pm: 0.6% of 10349 checklists7 pm: 0.3% of 6233 checklists8 pm: too few checklists (2002) to judge9 pm: too few checklists (392) to judge10 pm: too few checklists (186) to judge11 pm: too few checklists (87) 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
January0.3%0.4%0.1%0.4%
February0.2%0.4%0.2%0.1%
March0.3%0.3%0.4%0.2%
April0.3%0.4%0.7%1.0%
May0.6%0.5%0.4%0.2%
June0.1%0.2%0.1%0.2%
July0.2%0.3%0.2%0.4%
August0.8%0.5%0.8%0.7%
September0.8%1.0%1.5%1.8%
October1.4%0.8%0.4%0.3%
November0.2%0.2%0%0.1%
December0.1%0.1%0.3%0.2%

Neighboring states

  • Wisconsin: arrives mid July, in the same week than Iowa
  • Minnesota: arrives late February, 19 weeks earlier than Iowa
  • Illinois: arrives mid June, 4 weeks earlier than Iowa
  • Indiana: arrives early March, 18 weeks earlier than Iowa

Common questions

When do Peregrine Falcons arrive in Iowa?
Peregrine Falcons arrive in Iowa in mid July, peak in late September (1.6% of checklists), and most are gone by late October.
When do Peregrine Falcons leave Iowa?
Most Peregrine Falcons have left Iowa by late October, when reports fall below half their usual rate.
When is the best time to see a Peregrine Falcon in Iowa?
The Peregrine Falcon is reported most often in late September, on about 1.6% of Iowa checklists.
Where in Iowa are Peregrine Falcons seen most often?
By county, Jackson County, Louisa County, and Des Moines County have the highest peak reporting rates for the Peregrine Falcon (counties with at least 200 checklists).