WhenToBird

Cyanocitta cristata · Corvidae

When Do Blue Jays Arrive in Illinois?

Adult Blue Jay
Photo: Texas Bird Family, CC BY 4.0 via iNaturalist

The Blue Jay is in Illinois all year. It turns up on about 55% of checklists at its peak (late September) and on 25% in its quietest week (early March).

When to look

PresentAll year
Peak weekSep 22-30late September
Quietest weekMar 1-7early March

Best: late September. Here all year. Peak: on about 55% of Illinois checklists.

  1. Jancommon
  2. Febcommon
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octpeak season
  11. Novcommon
  12. Deccommon

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

0%20%40%60%Jan 1-7: 29% of 29700 checklistsJan 8-14: 27% of 20189 checklistsJan 15-21: 27% of 19784 checklistsJan 22-31: 27% of 26641 checklistsFeb 1-7: 28% of 20478 checklistsFeb 8-14: 28% of 21967 checklistsFeb 15-21: 26% of 28735 checklistsFeb 22-28: 26% of 24223 checklistsMar 1-7: 25% of 26775 checklistsMar 8-14: 25% of 27579 checklistsMar 15-21: 26% of 27193 checklistsMar 22-31: 28% of 42278 checklistsApr 1-7: 29% of 34579 checklistsApr 8-14: 31% of 38290 checklistsApr 15-21: 34% of 39261 checklistsApr 22-30: 42% of 59584 checklistsMay 1-7: 47% of 60485 checklistsMay 8-14: 47% of 59647 checklistsMay 15-21: 45% of 43173 checklistsMay 22-31: 41% of 47913 checklistsJun 1-7: 33% of 31151 checklistsJun 8-14: 33% of 27692 checklistsJun 15-21: 34% of 23983 checklistsJun 22-30: 33% of 28448 checklistsJul 1-7: 36% of 21273 checklistsJul 8-14: 35% of 19284 checklistsJul 15-21: 36% of 17712 checklistsJul 22-31: 35% of 24500 checklistsAug 1-7: 36% of 18498 checklistsAug 8-14: 37% of 19331 checklistsAug 15-21: 39% of 19983 checklistsAug 22-31: 42% of 31892 checklistsSep 1-7: 48% of 26396 checklistsSep 8-14: 52% of 25011 checklistsSep 15-21: 57% of 23597 checklistsSep 22-30: 57% of 30638 checklistsOct 1-7: 52% of 23949 checklistsOct 8-14: 51% of 24412 checklistsOct 15-21: 46% of 22359 checklistsOct 22-31: 44% of 29794 checklistsNov 1-7: 41% of 21877 checklistsNov 8-14: 37% of 19742 checklistsNov 15-21: 35% of 18989 checklistsNov 22-30: 36% of 23905 checklistsDec 1-7: 34% of 16935 checklistsDec 8-14: 33% of 16687 checklistsDec 15-21: 35% of 20931 checklistsDec 22-31: 33% 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. Edwards CountyBest late October · 27 checklists that week, 797 in all93%
  2. Schuyler CountyBest early October · 10 checklists that week, 617 in all90%
  3. Wabash CountyBest late October · 14 checklists that week, 602 in all89%
  4. Cass CountyBest mid September · 20 checklists that week, 1,262 in all89%
  5. Knox CountyBest mid September · 161 checklists that week, 6,781 in all89%
  6. Whiteside CountyBest mid September · 56 checklists that week, 4,111 in all89%

Best spots

Share of checklists at the peak
  1. Oakhurst Forest PreserveKane County, best late September · 22 checklists that week, 1,244 in all100%
  2. Waterfall GlenDuPage County, best early September · 27 checklists that week, 852 in all100%
  3. Delnor Woods ParkKane County, best early May · 24 checklists that week, 300 in all100%
  4. Salt Creek Woods Nature PreserveCook County, best the second week of September · 22 checklists that week, 955 in all100%
  5. Deer Grove WestCook County, best mid September · 24 checklists that week, 808 in all99%

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

Best time of day

In Illinois, the Blue Jay is most often listed on checklists started between 6 and 8 am (50% of those checklists).

0%20%40%60%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: 48% of 95511 checklists7 am: 51% of 164584 checklists8 am: 48% of 163654 checklists9 am: 44% of 141804 checklists10 am: 39% of 122882 checklists11 am: 33% of 100640 checklists12 pm: 30% of 89894 checklists1 pm: 30% of 82729 checklists2 pm: 27% of 79801 checklists3 pm: 24% of 82169 checklists4 pm: 25% of 75124 checklists5 pm: 28% of 57708 checklists6 pm: 26% 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
January29%27%27%27%
February28%28%26%26%
March25%25%26%28%
April29%31%34%42%
May47%47%45%41%
June33%33%34%33%
July36%35%36%35%
August36%37%39%42%
September48%52%57%57%
October52%51%46%44%
November41%37%35%36%
December34%33%35%33%

Neighboring states

  • Indiana: year-round, peaks early October
  • Wisconsin: year-round, peaks mid September
  • Michigan: year-round, peaks mid September
  • Iowa: year-round, peaks mid September

Common questions

When do Blue Jays arrive in Illinois?
The Blue Jay is in Illinois all year. It turns up on about 55% of checklists at its peak (late September) and on 25% in its quietest week (early March).
When do Blue Jays leave Illinois?
The Blue Jay does not leave Illinois: it is reported all year, from 25% of checklists in early March to 55% in late September.
When is the best time to see a Blue Jay in Illinois?
The Blue Jay is reported most often in late September, on about 55% of Illinois checklists.
Where in Illinois are Blue Jays seen most often?
By county, Edwards County, Schuyler County, and Wabash County have the highest peak reporting rates for the Blue Jay (counties with at least 200 checklists).