WhenToBird

Thryothorus ludovicianus · Troglodytidae

When Do Carolina Wrens Arrive in Iowa?

Adult Carolina Wren
Photo: northerly, CC BY 4.0 via iNaturalist

Carolina Wrens are in Iowa all year, but most are here in summer: numbers build from early July, peak in early September (7.1% of checklists), and fall back by late September. In the quietest week (the second week of March) they are still on about 2.4% of checklists.

When to look

Numbers buildJul 1-7early July
PeakSep 1-7early September
Fall back bySep 22-30late September
FewestMar 8-14the second week of March

Best: early September. Here all year; numbers build from early July and fall back by late September. Peak: on about 7.1% of Iowa checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julpeak season
  8. Augpeak season
  9. Seppeak season
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%2%4%6%8%Jan 1-7: 3.3% of 5551 checklistsJan 8-14: 2.5% of 3498 checklistsJan 15-21: 3.1% of 3803 checklistsJan 22-31: 3.1% of 4807 checklistsFeb 1-7: 3.0% of 3613 checklistsFeb 8-14: 4.5% of 4173 checklistsFeb 15-21: 2.7% of 5796 checklistsFeb 22-28: 2.7% of 4394 checklistsMar 1-7: 2.1% of 5295 checklistsMar 8-14: 2.4% of 5679 checklistsMar 15-21: 2.6% of 5418 checklistsMar 22-31: 3.3% of 8613 checklistsApr 1-7: 3.4% of 6970 checklistsApr 8-14: 4.4% of 7511 checklistsApr 15-21: 4.7% of 8321 checklistsApr 22-30: 5.1% of 11976 checklistsMay 1-7: 6.1% of 11725 checklistsMay 8-14: 5.5% of 12626 checklistsMay 15-21: 4.0% of 9372 checklistsMay 22-31: 3.9% of 10330 checklistsJun 1-7: 3.6% of 5472 checklistsJun 8-14: 4.7% of 4568 checklistsJun 15-21: 4.5% of 3870 checklistsJun 22-30: 4.5% of 4780 checklistsJul 1-7: 4.8% of 4201 checklistsJul 8-14: 5.6% of 3605 checklistsJul 15-21: 4.8% of 3621 checklistsJul 22-31: 5.4% of 5093 checklistsAug 1-7: 6.2% of 3931 checklistsAug 8-14: 6.2% of 3488 checklistsAug 15-21: 6.2% of 3802 checklistsAug 22-31: 7.1% of 6293 checklistsSep 1-7: 7.3% of 5328 checklistsSep 8-14: 6.8% of 4622 checklistsSep 15-21: 6.3% of 4367 checklistsSep 22-30: 4.9% of 6086 checklistsOct 1-7: 4.7% of 4708 checklistsOct 8-14: 3.7% of 4791 checklistsOct 15-21: 3.7% of 4429 checklistsOct 22-31: 3.7% of 5633 checklistsNov 1-7: 3.3% of 4090 checklistsNov 8-14: 3.1% of 3416 checklistsNov 15-21: 2.6% of 3398 checklistsNov 22-30: 3.4% of 4679 checklistsDec 1-7: 2.7% of 3442 checklistsDec 8-14: 2.6% of 3322 checklistsDec 15-21: 3.9% of 4619 checklistsDec 22-31: 3.4% 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. Poweshiek CountyBest the second week of August · 20 checklists that week, 1,402 in all42%
  2. Des Moines CountyBest early May · 67 checklists that week, 2,251 in all37%
  3. Henry CountyBest mid August · 22 checklists that week, 927 in all29%
  4. Scott CountyBest early September · 229 checklists that week, 11,116 in all27%
  5. Lucas CountyBest early February · 35 checklists that week, 2,217 in all27%
  6. Clinton CountyBest mid September · 20 checklists that week, 1,160 in all26%

Best spots

Share of checklists at the peak
  1. Mines of Spain State Recreation AreaDubuque County, best late August · 24 checklists that week, 754 in all63%
  2. Walnut Woods State ParkPolk County, best the second week of April · 29 checklists that week, 643 in all45%
  3. Mines of Spain State Recreation Area (Catfish Creek)Dubuque County, best the second week of September · 26 checklists that week, 244 in all40%
  4. Wildcat Den State ParkMuscatine County, best early May · 31 checklists that week, 395 in all36%
  5. Greenwood ParkPolk County, best early September · 26 checklists that week, 730 in all35%
  6. Hickory Hill ParkJohnson County, best late March · 37 checklists that week, 2,281 in all33%

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

Best time of day

In Iowa, the Carolina Wren is most often listed on checklists started between 6 and 8 am (8.6% 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: 10% of 11313 checklists7 am: 7.9% of 25717 checklists8 am: 5.8% of 29755 checklists9 am: 4.4% of 28897 checklists10 am: 3.8% of 26343 checklists11 am: 3.2% of 21210 checklists12 pm: 3.2% of 17662 checklists1 pm: 3.0% of 16595 checklists2 pm: 2.7% of 16405 checklists3 pm: 2.6% of 17030 checklists4 pm: 2.9% of 17378 checklists5 pm: 3.0% of 14251 checklists6 pm: 2.7% of 10349 checklists7 pm: 2.2% 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
January3.3%2.5%3.1%3.1%
February3.0%4.5%2.7%2.7%
March2.1%2.4%2.6%3.3%
April3.4%4.4%4.7%5.1%
May6.1%5.5%4.0%3.9%
June3.6%4.7%4.5%4.5%
July4.8%5.6%4.8%5.4%
August6.2%6.2%6.2%7.1%
September7.3%6.8%6.3%4.9%
October4.7%3.7%3.7%3.7%
November3.3%3.1%2.6%3.4%
December2.7%2.6%3.9%3.4%

Neighboring states

  • Missouri: year-round, peaks mid September
  • Illinois: year-round, peaks the second week of September
  • Nebraska: arrives late March, 13 weeks earlier than Iowa
  • Kansas: year-round, peaks the second week of July

Common questions

When do Carolina Wrens arrive in Iowa?
Carolina Wrens are in Iowa all year, but most are here in summer: numbers build from early July, peak in early September (7.1% of checklists), and fall back by late September. In the quietest week (the second week of March) they are still on about 2.4% of checklists.
When do Carolina Wrens leave Iowa?
Carolina Wrens never fully leave Iowa: numbers fall back below half their usual rate by late September, but some are still reported in every week, about 2.4% of checklists at the low.
When is the best time to see a Carolina Wren in Iowa?
The Carolina Wren is reported most often in early September, on about 7.1% of Iowa checklists.
Where in Iowa are Carolina Wrens seen most often?
By county, Poweshiek County, Des Moines County, and Henry County have the highest peak reporting rates for the Carolina Wren (counties with at least 200 checklists).