WhenToBird

Mimus polyglottos · Mimidae

When Do Northern Mockingbirds Arrive in Illinois?

Adult Northern Mockingbird
Photo: Bill Keim, CC BY 4.0 via iNaturalist

Northern Mockingbirds reach Illinois in mid September, are common by early October, peak in early July (2.5% of checklists), and most are gone by the second week of August.

When to look

First arrivalsSep 15-21mid September
Common byOct 1-7early October
PeakJul 1-7early July
Most gone byAug 8-14the second week of August

Best: early July. First arrivals mid September; most are gone by the second week of August. Peak: on about 2.5% of Illinois checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprcommon
  5. Maycommon
  6. Junpeak season
  7. Julpeak season
  8. Augcommon
  9. Sepcommon
  10. Octcommon
  11. Novcommon
  12. Deccommon

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

0%1%2%3%Jan 1-7: 1.5% of 29700 checklistsJan 8-14: 1.5% of 20189 checklistsJan 15-21: 1.5% of 19784 checklistsJan 22-31: 1.4% of 26641 checklistsFeb 1-7: 1.4% of 20478 checklistsFeb 8-14: 1.6% of 21967 checklistsFeb 15-21: 1.4% of 28735 checklistsFeb 22-28: 1.2% of 24223 checklistsMar 1-7: 1.0% of 26775 checklistsMar 8-14: 1.1% of 27579 checklistsMar 15-21: 1.2% of 27193 checklistsMar 22-31: 1.2% of 42278 checklistsApr 1-7: 1.3% of 34579 checklistsApr 8-14: 1.6% of 38290 checklistsApr 15-21: 1.7% of 39261 checklistsApr 22-30: 1.9% of 59584 checklistsMay 1-7: 1.8% of 60485 checklistsMay 8-14: 1.9% of 59647 checklistsMay 15-21: 1.4% of 43173 checklistsMay 22-31: 2.0% of 47913 checklistsJun 1-7: 1.7% of 31151 checklistsJun 8-14: 2.3% of 27692 checklistsJun 15-21: 2.5% of 23983 checklistsJun 22-30: 2.5% of 28448 checklistsJul 1-7: 2.6% of 21273 checklistsJul 8-14: 2.5% of 19284 checklistsJul 15-21: 2.3% of 17712 checklistsJul 22-31: 1.9% of 24500 checklistsAug 1-7: 1.7% of 18498 checklistsAug 8-14: 1.2% of 19331 checklistsAug 15-21: 1.1% of 19983 checklistsAug 22-31: 0.9% of 31892 checklistsSep 1-7: 0.7% of 26396 checklistsSep 8-14: 0.8% of 25011 checklistsSep 15-21: 1.0% of 23597 checklistsSep 22-30: 0.9% of 30638 checklistsOct 1-7: 1.3% of 23949 checklistsOct 8-14: 1.7% of 24412 checklistsOct 15-21: 1.3% of 22359 checklistsOct 22-31: 1.1% of 29794 checklistsNov 1-7: 1.1% of 21877 checklistsNov 8-14: 1.0% of 19742 checklistsNov 15-21: 1.0% of 18989 checklistsNov 22-30: 1.1% of 23905 checklistsDec 1-7: 1.1% of 16935 checklistsDec 8-14: 1.4% of 16687 checklistsDec 15-21: 1.5% of 20931 checklistsDec 22-31: 2.0% of 29011 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 Illinois 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 Illinois

Best counties

Share of checklists at the peak
  1. Monroe CountyBest early May · 114 checklists that week, 2,547 in all50%
  2. Lawrence CountyBest late December · 25 checklists that week, 719 in all48%
  3. Edwards CountyBest late September · 24 checklists that week, 797 in all48%
  4. Jackson CountyBest mid October · 211 checklists that week, 18,590 in all40%
  5. Massac CountyBest the second week of December · 13 checklists that week, 1,916 in all37%
  6. Hamilton CountyBest early July · 16 checklists that week, 619 in all36%

Best spots

Share of checklists at the peak
  1. Carbondale ReservoirJackson County, best the second week of May · 36 checklists that week, 1,735 in all79%
  2. Oak Forest Heritage PreserveCook County, best the second week of February · 23 checklists that week, 476 in all47%
  3. Horseshoe Lake-Madison State Fish and Wildlife AreaMadison County, best late April · 24 checklists that week, 280 in all44%
  4. Campus LakeJackson County, best late April · 26 checklists that week, 450 in all43%
  5. Deer LakeJackson County, best the second week of February · 30 checklists that week, 764 in all42%

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

Best time of day

In Illinois, the Northern Mockingbird is most often listed on checklists started between 6 and 8 am (2.0% of those checklists).

0%1%2%3%12 am: too few checklists (484) to judge1 am: too few checklists (631) to judge2 am: too few checklists (485) to judge3 am: too few checklists (610) to judge4 am: too few checklists (2321) to judge5 am: too few checklists (23536) to judge6 am: 2.2% of 95511 checklists7 am: 1.9% of 164584 checklists8 am: 1.8% of 163654 checklists9 am: 1.5% of 141804 checklists10 am: 1.3% of 122882 checklists11 am: 1.1% of 100640 checklists12 pm: 1.1% of 89894 checklists1 pm: 1.1% of 82729 checklists2 pm: 1.1% of 79801 checklists3 pm: 1.2% of 82169 checklists4 pm: 1.4% of 75124 checklists5 pm: 1.6% of 57708 checklists6 pm: 1.8% of 41843 checklists7 pm: too few checklists (20943) to judge8 pm: too few checklists (6131) to judge9 pm: too few checklists (1677) to judge10 pm: too few checklists (843) to judge11 pm: too few checklists (448) 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
January1.5%1.5%1.5%1.4%
February1.4%1.6%1.4%1.2%
March1.0%1.1%1.2%1.2%
April1.3%1.6%1.7%1.9%
May1.8%1.9%1.4%2.0%
June1.7%2.3%2.5%2.5%
July2.6%2.5%2.3%1.9%
August1.7%1.2%1.1%0.9%
September0.7%0.8%1.0%0.9%
October1.3%1.7%1.3%1.1%
November1.1%1.0%1.0%1.1%
December1.1%1.4%1.5%2.0%

Neighboring states

  • Indiana: arrives late March, 23 weeks earlier than Illinois
  • Missouri: arrives mid March, 24 weeks earlier than Illinois
  • Kentucky: year-round, peaks the second week of October
  • Ohio: year-round, peaks late June

Common questions

When do Northern Mockingbirds arrive in Illinois?
Northern Mockingbirds reach Illinois in mid September, are common by early October, peak in early July (2.5% of checklists), and most are gone by the second week of August.
When do Northern Mockingbirds leave Illinois?
Most Northern Mockingbirds have left Illinois by the second week of August, when reports fall below half their usual rate. Stragglers are still reported until late August.
When is the best time to see a Northern Mockingbird in Illinois?
The Northern Mockingbird is reported most often in early July, on about 2.5% of Illinois checklists.
Where in Illinois are Northern Mockingbirds seen most often?
By county, Monroe County, Lawrence County, and Edwards County have the highest peak reporting rates for the Northern Mockingbird (counties with at least 200 checklists).