WhenToBird

2 oriole species in Iowa

When Do Orioles Arrive in Iowa?

Adult male Baltimore Oriole
Photo: Daughter Dad, CC BY 4.0 via iNaturalist

Baltimore Orioles and Orchard Orioles are the orioles you are most likely to see in Iowa. Baltimore Orioles arrive in Iowa in late April, peak in mid May (55% of checklists), and most are gone by early September.

Orioles here are the birds (Baltimore, Orchard, Bullock's and relatives), not the baseball team.

When to look

First arrivalsApr 22-30late April
Common byApr 22-30late April
PeakMay 15-21mid May
Most gone bySep 1-7early September

Best: mid May. First arrivals late April; most are gone by early September. Peak: on about 55% of Iowa checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Apruncommon
  5. Maypeak season
  6. Junpeak season
  7. Julcommon
  8. Augcommon
  9. Sepuncommon
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

Orioles in Iowa, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Baltimore OrioleApr 22-30Apr 22-30May 15-21Sep 1-755%
Orchard OrioleApr 22-30May 1-7Jun 22-30Jul 22-3114%
0%20%40%60%Baltimore OrioleOrchard OrioleJanFebMarAprMayJunJulAugSepOctNovDec
  • Baltimore Oriole
  • Orchard Oriole
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 Baltimore Oriole

Share of checklists at the peak
  1. Lyon CountyBest mid May · 35 checklists that week, 498 in all81%
  2. Madison CountyBest mid May · 104 checklists that week, 2,941 in all74%
  3. Keokuk CountyBest mid May · 15 checklists that week, 243 in all74%
  4. Shelby CountyBest mid June · 14 checklists that week, 354 in all72%
  5. Clayton CountyBest mid May · 44 checklists that week, 1,181 in all72%
  6. Delaware CountyBest the second week of May · 23 checklists that week, 616 in all70%

Common questions

When do orioles arrive in Iowa?
Baltimore Orioles arrive in Iowa in late April, peak in mid May (55% of checklists), and most are gone by early September.
When do orioles leave Iowa?
Most Baltimore Orioles have left Iowa by early September, when reports fall below half their usual rate. Stragglers are still reported until the second week of September.
When is the best time to see orioles in Iowa?
The Baltimore Oriole is reported most often in mid May, on about 55% of Iowa checklists.
Which orioles are in Iowa?
Baltimore Oriole and Orchard Oriole are reported regularly; the Baltimore Oriole is the most common.