WhenToBird

2 grosbeak species in Iowa

When Do Grosbeaks Arrive in Iowa?

Adult male Rose-breasted Grosbeak
Photo: Nancy Overholtz, CC BY-SA 4.0 via iNaturalist

Rose-breasted Grosbeaks reach Iowa in mid April, are common by late April, peak in mid May (41% of checklists), and most are gone by mid September. They are by far the most reported grosbeaks in Iowa.

When to look

First arrivalsApr 15-21mid April
Common byApr 22-30late April
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 41% of Iowa checklists.

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

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

Grosbeaks in Iowa, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
Rose-breasted GrosbeakApr 15-21Apr 22-30May 15-21Sep 15-2141%
Blue GrosbeakMay 22-31Jun 1-7Aug 8-14Sep 1-74.1%
0%20%40%60%Rose-breasted GrosbeakBlue GrosbeakJanFebMarAprMayJunJulAugSepOctNovDec
  • Rose-breasted Grosbeak
  • Blue Grosbeak
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 Rose-breasted Grosbeak

Share of checklists at the peak
  1. Louisa CountyBest the second week of May · 56 checklists that week, 1,639 in all67%
  2. Lucas CountyBest the second week of May · 86 checklists that week, 2,217 in all64%
  3. Monona CountyBest the second week of June · 36 checklists that week, 655 in all63%
  4. Washington CountyBest the second week of May · 85 checklists that week, 1,746 in all63%
  5. Monroe CountyBest late May · 18 checklists that week, 257 in all63%
  6. Webster CountyBest the second week of May · 24 checklists that week, 635 in all61%

Common questions

When do grosbeaks arrive in Iowa?
Rose-breasted Grosbeaks reach Iowa in mid April, are common by late April, peak in mid May (41% of checklists), and most are gone by mid September. They are by far the most reported grosbeaks in Iowa.
When do grosbeaks leave Iowa?
Most Rose-breasted Grosbeaks have left Iowa by mid September, when reports fall below half their usual rate. Stragglers are still reported until early October.
When is the best time to see grosbeaks in Iowa?
The Rose-breasted Grosbeak is reported most often in mid May, on about 41% of Iowa checklists.
Which grosbeaks are in Iowa?
Rose-breasted Grosbeak and Blue Grosbeak are reported regularly; the Rose-breasted Grosbeak is the most common.