WhenToBird

Quiscalus quiscula · Icteridae

When Do Common Grackles Arrive in Iowa?

Adult Common Grackle
Photo: Derek Spencer, CC BY 4.0 via iNaturalist

Common Grackles reach Iowa in late February, are common by the second week of March, peak in the second week of June (36% of checklists), and most are gone by late July.

When to look

First arrivalsFeb 22-28late February
Common byMar 8-14the second week of March
PeakJun 8-14the second week of June
Most gone byJul 22-31late July

Best: the second week of June. First arrivals late February; most are gone by late July. Peak: on about 36% of Iowa checklists.

  1. Jannot usually seen
  2. Febrare
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Junpeak season
  7. Julpeak season
  8. Auguncommon
  9. Sepuncommon
  10. Octuncommon
  11. Novuncommon
  12. Decrare

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

0%10%20%30%40%Jan 1-7: 1.0% of 5551 checklistsJan 8-14: 0.8% of 3498 checklistsJan 15-21: 0.5% of 3803 checklistsJan 22-31: 0.8% of 4807 checklistsFeb 1-7: 0.5% of 3613 checklistsFeb 8-14: 0.7% of 4173 checklistsFeb 15-21: 1.3% of 5796 checklistsFeb 22-28: 2.8% of 4394 checklistsMar 1-7: 8.2% of 5295 checklistsMar 8-14: 16% of 5679 checklistsMar 15-21: 23% of 5418 checklistsMar 22-31: 28% of 8613 checklistsApr 1-7: 28% of 6970 checklistsApr 8-14: 28% of 7511 checklistsApr 15-21: 29% of 8321 checklistsApr 22-30: 30% of 11976 checklistsMay 1-7: 30% of 11725 checklistsMay 8-14: 32% of 12626 checklistsMay 15-21: 34% of 9372 checklistsMay 22-31: 35% of 10330 checklistsJun 1-7: 37% of 5472 checklistsJun 8-14: 35% of 4568 checklistsJun 15-21: 37% of 3870 checklistsJun 22-30: 32% of 4780 checklistsJul 1-7: 28% of 4201 checklistsJul 8-14: 23% of 3605 checklistsJul 15-21: 17% of 3621 checklistsJul 22-31: 14% of 5093 checklistsAug 1-7: 10% of 3931 checklistsAug 8-14: 8.5% of 3488 checklistsAug 15-21: 5.9% of 3802 checklistsAug 22-31: 4.6% of 6293 checklistsSep 1-7: 4.3% of 5328 checklistsSep 8-14: 4.2% of 4622 checklistsSep 15-21: 5.2% of 4367 checklistsSep 22-30: 8.0% of 6086 checklistsOct 1-7: 9.0% of 4708 checklistsOct 8-14: 11% of 4791 checklistsOct 15-21: 11% of 4429 checklistsOct 22-31: 9.2% of 5633 checklistsNov 1-7: 6.8% of 4090 checklistsNov 8-14: 3.4% of 3416 checklistsNov 15-21: 2.8% of 3398 checklistsNov 22-30: 1.8% of 4679 checklistsDec 1-7: 1.3% of 3442 checklistsDec 8-14: 1.5% of 3322 checklistsDec 15-21: 1.0% of 4619 checklistsDec 22-31: 1.0% 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. Shelby CountyBest mid June · 14 checklists that week, 354 in all72%
  2. Cass CountyBest early June · 12 checklists that week, 449 in all72%
  3. Calhoun CountyBest late June · 20 checklists that week, 446 in all71%
  4. Sioux CountyBest mid May · 60 checklists that week, 1,159 in all70%
  5. Dickinson CountyBest late May · 136 checklists that week, 2,030 in all69%
  6. Emmet CountyBest late May · 45 checklists that week, 322 in all68%

Best spots

Share of checklists at the peak
  1. Ada Hayden Heritage ParkStory County, best the second week of May · 39 checklists that week, 1,681 in all90%
  2. Brenton ArboretumDallas County, best the second week of May · 22 checklists that week, 426 in all89%
  3. Colo Wetland Wildlife Management AreaStory County, best late May · 25 checklists that week, 567 in all87%
  4. John Deere MarshDubuque County, best late June · 24 checklists that week, 1,952 in all86%
  5. Koutny Pond/Hoffman WoodsBuchanan County, best late April · 32 checklists that week, 318 in all84%
  6. Tedesco Environmental Learning Corridor (TELC)Story County, best the second week of May · 31 checklists that week, 969 in all84%

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

Best time of day

In Iowa, the Common Grackle is most often listed on checklists started between 6 and 8 pm (25% of those checklists).

0%10%20%30%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: 28% of 11313 checklists7 am: 20% of 25717 checklists8 am: 18% of 29755 checklists9 am: 16% of 28897 checklists10 am: 13% of 26343 checklists11 am: 13% of 21210 checklists12 pm: 14% of 17662 checklists1 pm: 13% of 16595 checklists2 pm: 12% of 16405 checklists3 pm: 13% of 17030 checklists4 pm: 16% of 17378 checklists5 pm: 22% of 14251 checklists6 pm: 25% of 10349 checklists7 pm: 25% 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
January1.0%0.8%0.5%0.8%
February0.5%0.7%1.3%2.8%
March8.2%16%23%28%
April28%28%29%30%
May30%32%34%35%
June37%35%37%32%
July28%23%17%14%
August10%8.5%5.9%4.6%
September4.3%4.2%5.2%8.0%
October9.0%11%11%9.2%
November6.8%3.4%2.8%1.8%
December1.3%1.5%1.0%1.0%

Neighboring states

  • Missouri: arrives the second week of March, 2 weeks later than Iowa
  • Wisconsin: arrives late February, in the same week than Iowa
  • Minnesota: arrives early March, 1 week later than Iowa
  • Illinois: arrives the second week of February, 2 weeks earlier than Iowa

Common questions

When do Common Grackles arrive in Iowa?
Common Grackles reach Iowa in late February, are common by the second week of March, peak in the second week of June (36% of checklists), and most are gone by late July.
When do Common Grackles leave Iowa?
Most Common Grackles have left Iowa by late July, when reports fall below half their usual rate. Stragglers are still reported until mid November.
When is the best time to see a Common Grackle in Iowa?
The Common Grackle is reported most often in the second week of June, on about 36% of Iowa checklists.
Where in Iowa are Common Grackles seen most often?
By county, Shelby County, Cass County, and Calhoun County have the highest peak reporting rates for the Common Grackle (counties with at least 200 checklists).