WhenToBird

6 swallow species in Iowa

When Do Swallows Arrive in Iowa?

Adult Barn Swallow
Photo: Diego González Dopico, CC BY 4.0 via iNaturalist

Barn Swallows, Tree Swallows, and Cliff Swallows are the swallows you are most likely to see in Iowa. Barn Swallows reach Iowa in the second week of April, are common by late April, peak in the second week of August (40% of checklists), and most are gone by the second week of September.

When to look

First arrivalsApr 8-14the second week of April
Common byApr 22-30late April
PeakAug 8-14the second week of August
Most gone bySep 8-14the second week of September

Best: the second week of August. First arrivals the second week of April; most are gone by the second week of September. Peak: on about 40% of Iowa checklists.

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

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

Swallows in Iowa, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Barn SwallowApr 8-14Apr 22-30Aug 8-14Sep 8-1440%
Tree SwallowMar 15-21Apr 1-7Apr 22-30Oct 15-2128%
Cliff SwallowApr 15-21May 1-7Jul 1-7Sep 1-718%
Purple MartinApr 1-7Apr 15-21Aug 1-7Aug 22-3111%
Chimney SwiftApr 15-21May 1-7May 15-21Sep 15-2111%
Bank SwallowApr 22-30Apr 22-30Aug 8-14Sep 8-146.3%
0%20%40%60%Barn SwallowTree SwallowCliff SwallowPurple MartinJanFebMarAprMayJunJulAugSepOctNovDec
  • Barn Swallow
  • Tree Swallow
  • Cliff Swallow
  • Purple Martin
Share of complete checklists reporting each species, by week (4 per month). Gaps: fewer than 10 checklists that week.

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.

Where in Iowa

Best counties for Barn Swallow

Share of checklists at the peak
  1. Pocahontas CountyBest early July · 14 checklists that week, 735 in all89%
  2. Calhoun CountyBest early July · 20 checklists that week, 446 in all77%
  3. Howard CountyBest late June · 13 checklists that week, 334 in all72%
  4. Harrison CountyBest the second week of July · 19 checklists that week, 1,977 in all70%
  5. Ringgold CountyBest the second week of August · 20 checklists that week, 1,141 in all69%
  6. Palo Alto CountyBest late July · 13 checklists that week, 460 in all69%

All swallows in Iowa

6 species are reported regularly: 6 are summer visitors.

#SpeciesPatternThrough the yearFirst arrivalsPeakPeak %
1Barn SwallowSummer visitorApr 8-14Aug 8-1440%
2Tree SwallowSummer visitorMar 15-21Apr 22-3028%
3Cliff SwallowSummer visitorApr 15-21Jul 1-718%
4Purple MartinSummer visitorApr 1-7Aug 1-711%
5Northern Rough-winged SwallowSummer visitorApr 8-14May 8-1410%
6Bank SwallowSummer visitorApr 22-30Aug 8-146.3%

Common questions

When do swallows arrive in Iowa?
Barn Swallows reach Iowa in the second week of April, are common by late April, peak in the second week of August (40% of checklists), and most are gone by the second week of September.
When do swallows leave Iowa?
Most Barn Swallows have left Iowa by the second week of 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 swallows in Iowa?
The Barn Swallow is reported most often in the second week of August, on about 40% of Iowa checklists.
Which swallows are in Iowa?
Barn Swallow, Tree Swallow, Cliff Swallow, Purple Martin, Chimney Swift, and Bank Swallow are reported regularly; the Barn Swallow is the most common.