WhenToBird

Chordeiles minor · Caprimulgidae

When Do Common Nighthawks Arrive in Illinois?

Adult Common Nighthawk
Photo: Donald Davesne, CC BY 4.0 via iNaturalist

Common Nighthawks mostly pass through Illinois: they arrive in the second week of May, peak in early September (7.5% of checklists), and most are gone by late September.

When to look

First arrivalsMay 8-14the second week of May
Common byMay 8-14the second week of May
PeakSep 1-7early September
Most gone bySep 22-30late September

Best: early September. First arrivals the second week of May; most are gone by late September. Peak: on about 7.5% of Illinois checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprnot usually seen
  5. Mayuncommon
  6. Jununcommon
  7. Juluncommon
  8. Augpeak season
  9. Seppeak season
  10. Octrare
  11. Novnot usually seen
  12. Decnot usually seen

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

0%5%10%Jan 1-7: 0% of 29700 checklistsJan 8-14: 0% of 20189 checklistsJan 15-21: 0% of 19784 checklistsJan 22-31: 0% of 26641 checklistsFeb 1-7: 0% of 20478 checklistsFeb 8-14: 0% of 21967 checklistsFeb 15-21: 0% of 28735 checklistsFeb 22-28: 0% of 24223 checklistsMar 1-7: 0% of 26775 checklistsMar 8-14: 0% of 27579 checklistsMar 15-21: 0% of 27193 checklistsMar 22-31: 0% of 42278 checklistsApr 1-7: 0% of 34579 checklistsApr 8-14: 0% of 38290 checklistsApr 15-21: 0% of 39261 checklistsApr 22-30: 0.1% of 59584 checklistsMay 1-7: 0.5% of 60485 checklistsMay 8-14: 1.6% of 59647 checklistsMay 15-21: 3.4% of 43173 checklistsMay 22-31: 3.2% of 47913 checklistsJun 1-7: 1.4% of 31151 checklistsJun 8-14: 1.5% of 27692 checklistsJun 15-21: 1.7% of 23983 checklistsJun 22-30: 1.6% of 28448 checklistsJul 1-7: 1.3% of 21273 checklistsJul 8-14: 1.1% of 19284 checklistsJul 15-21: 1.3% of 17712 checklistsJul 22-31: 1.2% of 24500 checklistsAug 1-7: 1.2% of 18498 checklistsAug 8-14: 1.5% of 19331 checklistsAug 15-21: 3.7% of 19983 checklistsAug 22-31: 8.9% of 31892 checklistsSep 1-7: 7.3% of 26396 checklistsSep 8-14: 5.9% of 25011 checklistsSep 15-21: 3.4% of 23597 checklistsSep 22-30: 1.2% of 30638 checklistsOct 1-7: 0.6% of 23949 checklistsOct 8-14: 0.2% of 24412 checklistsOct 15-21: 0.1% of 22359 checklistsOct 22-31: 0.1% of 29794 checklistsNov 1-7: 0% of 21877 checklistsNov 8-14: 0% of 19742 checklistsNov 15-21: 0% of 18989 checklistsNov 22-30: 0% of 23905 checklistsDec 1-7: 0% of 16935 checklistsDec 8-14: 0% of 16687 checklistsDec 15-21: 0% of 20931 checklistsDec 22-31: 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. Winnebago CountyBest early September · 306 checklists that week, 18,333 in all18%
  2. Cass CountyBest early September · 18 checklists that week, 1,262 in all16%
  3. Knox CountyBest the second week of September · 165 checklists that week, 6,781 in all14%
  4. Lee CountyBest the second week of September · 124 checklists that week, 6,175 in all13%
  5. Whiteside CountyBest the second week of September · 82 checklists that week, 4,111 in all13%
  6. Jefferson CountyBest the second week of May · 114 checklists that week, 2,716 in all13%

Best spots

Share of checklists at the peak
  1. Meadowbrook ParkChampaign County, best mid August · 25 checklists that week, 1,816 in all32%
  2. Ms Rv Pools 11-22 Recreation Area (south)Whiteside County, best late June · 21 checklists that week, 204 in all31%
  3. Senior Citizens Meml.Cook County, best late August · 25 checklists that week, 571 in all31%
  4. Brunner Family Forest PreserveKane County, best early September · 22 checklists that week, 1,151 in all30%
  5. Sand Pond (Kellogg Creek)Lake County, best early September · 20 checklists that week, 544 in all29%

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

Best time of day

In Illinois, the Common Nighthawk is most often listed on checklists started between 5 and 7 pm (5.0% of those checklists).

0%2%4%6%8%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: 0.8% of 95511 checklists7 am: 0.5% of 164584 checklists8 am: 0.4% of 163654 checklists9 am: 0.3% of 141804 checklists10 am: 0.2% of 122882 checklists11 am: 0.2% of 100640 checklists12 pm: 0.3% of 89894 checklists1 pm: 0.4% of 82729 checklists2 pm: 0.4% of 79801 checklists3 pm: 0.6% of 82169 checklists4 pm: 1.4% of 75124 checklists5 pm: 3.4% of 57708 checklists6 pm: 7.1% 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
January0%0%0%0%
February0%0%0%0%
March0%0%0%0%
April0%0%0%0.1%
May0.5%1.6%3.4%3.2%
June1.4%1.5%1.7%1.6%
July1.3%1.1%1.3%1.2%
August1.2%1.5%3.7%8.9%
September7.3%5.9%3.4%1.2%
October0.6%0.2%0.1%0.1%
November0%0%0%0%
December0%0%0%0%

Neighboring states

  • Indiana: arrives early May, 1 week earlier than Illinois
  • Wisconsin: arrives the second week of August, 12 weeks later than Illinois
  • Michigan: arrives the second week of May, in the same week than Illinois
  • Iowa: arrives the second week of May, in the same week than Illinois

Common questions

When do Common Nighthawks arrive in Illinois?
Common Nighthawks mostly pass through Illinois: they arrive in the second week of May, peak in early September (7.5% of checklists), and most are gone by late September.
When do Common Nighthawks leave Illinois?
Most Common Nighthawks have left Illinois by late September, when reports fall below half their usual rate.
When is the best time to see a Common Nighthawk in Illinois?
The Common Nighthawk is reported most often in early September, on about 7.5% of Illinois checklists.
Where in Illinois are Common Nighthawks seen most often?
By county, Winnebago County, Cass County, and Knox County have the highest peak reporting rates for the Common Nighthawk (counties with at least 200 checklists).