WhenToBird

Chaetura pelagica · Apodidae

When Do Chimney Swifts Arrive in Iowa?

Adult Chimney Swift
Photo: Ali Campbell, CC BY 4.0 via iNaturalist

Chimney Swifts reach Iowa in mid April, are common by early May, peak in mid May (11% of checklists), and most are gone by mid September.

When to look

First arrivalsApr 15-21mid April
Common byMay 1-7early May
PeakMay 15-21mid May
Most gone bySep 15-21mid September

Best: mid May. First arrivals mid April; most are gone by mid September. Peak: on about 11% of Iowa checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octuncommon
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%15%Jan 1-7: 0% of 5551 checklistsJan 8-14: 0% of 3498 checklistsJan 15-21: 0% of 3803 checklistsJan 22-31: 0% of 4807 checklistsFeb 1-7: 0% of 3613 checklistsFeb 8-14: 0% of 4173 checklistsFeb 15-21: 0% of 5796 checklistsFeb 22-28: 0% of 4394 checklistsMar 1-7: 0% of 5295 checklistsMar 8-14: 0% of 5679 checklistsMar 15-21: 0% of 5418 checklistsMar 22-31: 0% of 8613 checklistsApr 1-7: 0% of 6970 checklistsApr 8-14: 0.1% of 7511 checklistsApr 15-21: 0.2% of 8321 checklistsApr 22-30: 2.3% of 11976 checklistsMay 1-7: 7.5% of 11725 checklistsMay 8-14: 10% of 12626 checklistsMay 15-21: 11% of 9372 checklistsMay 22-31: 11% of 10330 checklistsJun 1-7: 9.0% of 5472 checklistsJun 8-14: 9.1% of 4568 checklistsJun 15-21: 8.7% of 3870 checklistsJun 22-30: 10% of 4780 checklistsJul 1-7: 10% of 4201 checklistsJul 8-14: 9.3% of 3605 checklistsJul 15-21: 9.9% of 3621 checklistsJul 22-31: 10% of 5093 checklistsAug 1-7: 9.6% of 3931 checklistsAug 8-14: 8.8% of 3488 checklistsAug 15-21: 9.2% of 3802 checklistsAug 22-31: 9.2% of 6293 checklistsSep 1-7: 8.2% of 5328 checklistsSep 8-14: 8.1% of 4622 checklistsSep 15-21: 5.6% of 4367 checklistsSep 22-30: 4.2% of 6086 checklistsOct 1-7: 3.5% of 4708 checklistsOct 8-14: 1.7% of 4791 checklistsOct 15-21: 0.3% of 4429 checklistsOct 22-31: 0% of 5633 checklistsNov 1-7: 0% of 4090 checklistsNov 8-14: 0% of 3416 checklistsNov 15-21: 0% of 3398 checklistsNov 22-30: 0% of 4679 checklistsDec 1-7: 0% of 3442 checklistsDec 8-14: 0% of 3322 checklistsDec 15-21: 0% of 4619 checklistsDec 22-31: 0% 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. Pocahontas CountyBest early July · 14 checklists that week, 735 in all63%
  2. Des Moines CountyBest the second week of September · 40 checklists that week, 2,251 in all38%
  3. Wapello CountyBest the second week of July · 10 checklists that week, 654 in all35%
  4. Bremer CountyBest the second week of August · 35 checklists that week, 3,421 in all32%
  5. Carroll CountyBest early August · 12 checklists that week, 1,515 in all32%
  6. Poweshiek CountyBest late May · 62 checklists that week, 1,402 in all32%

Best spots

Share of checklists at the peak
  1. Trestle to Trestle TrailPolk County, best late May · 20 checklists that week, 434 in all62%
  2. Greenwood ParkPolk County, best late May · 70 checklists that week, 730 in all54%
  3. Kuehn Conservation AreaDallas County, best mid May · 20 checklists that week, 219 in all49%
  4. Carr ParkStory County, best late May · 64 checklists that week, 1,200 in all46%
  5. Reactor WoodsStory County, best mid May · 34 checklists that week, 397 in all45%

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

Best time of day

In Iowa, the Chimney Swift is most often listed on checklists started between 6 and 8 pm (9.6% of those checklists).

0%5%10%15%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: 8.7% of 11313 checklists7 am: 4.8% of 25717 checklists8 am: 3.8% of 29755 checklists9 am: 3.2% of 28897 checklists10 am: 2.9% of 26343 checklists11 am: 2.6% of 21210 checklists12 pm: 3.0% of 17662 checklists1 pm: 3.1% of 16595 checklists2 pm: 2.5% of 16405 checklists3 pm: 3.0% of 17030 checklists4 pm: 3.6% of 17378 checklists5 pm: 5.6% of 14251 checklists6 pm: 8.2% of 10349 checklists7 pm: 12% 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%0%0%0%
February0%0%0%0%
March0%0%0%0%
April0%0.1%0.2%2.3%
May7.5%10%11%11%
June9.0%9.1%8.7%10%
July10%9.3%9.9%10%
August9.6%8.8%9.2%9.2%
September8.2%8.1%5.6%4.2%
October3.5%1.7%0.3%0%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Missouri: arrives the second week of April, 1 week earlier than Iowa
  • Wisconsin: arrives late April, 1 week later than Iowa
  • Minnesota: arrives late April, 1 week later than Iowa
  • Illinois: arrives mid April, in the same week than Iowa

Common questions

When do Chimney Swifts arrive in Iowa?
Chimney Swifts reach Iowa in mid April, are common by early May, peak in mid May (11% of checklists), and most are gone by mid September.
When do Chimney Swifts leave Iowa?
Most Chimney Swifts have left Iowa by mid September, when reports fall below half their usual rate. Stragglers are still reported until the second week of October.
When is the best time to see a Chimney Swift in Iowa?
The Chimney Swift is reported most often in mid May, on about 11% of Iowa checklists.
Where in Iowa are Chimney Swifts seen most often?
By county, Pocahontas County, Des Moines County, and Wapello County have the highest peak reporting rates for the Chimney Swift (counties with at least 200 checklists).